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*^ /y DEPARTMENT OF MARINE BIOLOGY 

^zhi^'j-oyj ■ •^■^^ OF 

THE CARNEGIE INSTITUTION OF WASHINGTON 
ALFRED G. MAYOR, Director 



VOLUME XIV 



EXPERIMENTS IN THE BEEEDING OF CEEIONS 



BY 
PAUL BARTSCH 

Curator of Marine Invertebrates, United States National Museum 





WASHINGTON, D. C. 
Published by the Carnegie Institution of Washington 

1920 



CARNEGIE INSTITUTION OF WASHINGTON 
Publication No. 282 



PRESS OF GIBSON BROTHERS, INC. 
WASHINGTON, D. C. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



By Paul Bartsch. 



In 1912, by invitation from the Director of the Marine Biological 
Laboratory of the Carnegie Institution of Washington, and through 
the courtesy of the Secretary of the Smithsonian Institution, I had an 
opportunity to visit the Bahamas and to make personal observations 
upon the Cerions on New Providence and on Andros in the region of 
South Bight. 

On this expedition we found that Cerions were very abundant 
wherever they occur, that they live close to the seashore, but never- 
theless remain well beyond the reach of the ocean spray. They never, 
therefore, live outside of the hurricane rampart of the exposed shores. 
They are usually on the lowland flats, but under favorable circum- 
stances may climb the hills, for example Driggs Hill or Morgan's Bluff 
at Andros and the sea bluff at Jeremie, Haiti. This partiality to the 
coast lands is probably responsible for their discontinuous distribution, 
practically resulting in the formation of isolated colonies, and a great 
number of closely related forms scattered over the entire Archipelago 
of the Bahamas. 

By taking material gathered from such a colony and noting all 
measurable characters presented by its members, one obtains a mode 
different from that which may be secured in a similar manner from 
an adjacent colony. Each colony, therefore, presents certain slight 
characters by which we can distinguish its members from those of other 
colonies. 

The question arises, are the forms in the various colonies fixed forms; 
that is, will generation after generation yield the same mode in measure- 
ments, or will changes in the local environment from season to season 
affect the developing organisms to such an extent as to produce an 
unending series of slight variations? These were the problems that 
called for a solution. The hope of throwing some light upon these 
questions prompted the breeding experiments which were started in 
1912 and have been followed up ever since, and upon which the follow- 
ing reports have been published from time to time : 

Planting Bahama Cerions upon the Florida Keys, Year Book No. 11 of the Carnegie Insti- 
tution of Washington, 1912, pp. 129-i31. 
Report of Results of the Planting of Bahama Cerions on the Florida Keys, Year Book No. 

12 of the Carnegie Institution of Washington, 1913, pp. 169-172. 
Prehminary Report on the Bahama Cerions planted on the Florida Keys, Year Book No. 

13 of the Carnegie Institution of Washington, 1915, p. 196. 

Experiments with Cerions in the Florida Keys, Smithsonian Miscellaneous Collections No. 
6, 1915, illustrations 38-40. 



4 EXPERIMENTS IN THE BREEDING OF CERIONS. 

Report on the Bahama Cerions planted on the Florida Keys, Carnegie Inst. Wash. Pub. 

No. 212, 1915, pp. 203-212, plates 1-8. 
Report on Bahama Cerions planted on the Florida Keys, Year Book No. 14 of the Carnegie 

Institution of Washington, 1915, pp. 194-196. 
Report on the Bahama Cerions planted on the Florida Keys, Annual Report of the Director 

of Department of Marine Biology, Carnegie Institution of Washington, extract 

from Year Book No. 15 for the year 1916, pp. 179-182. 
Visit to the Cerion Colonies in Florida, Smithsonian Miscellaneous Collections, vol. 66, No. 

17, 1917, pp. 41-44. 
A Visit to the Cerion Colonies in Florida, Smithsonian Miscellaneous Collections, vol. 68, 

No. 12, June, 1918, pp. 48-49. 

The Florida Keys were considered to be a favorable region into which 
these Bahama forms might be introduced, for these keys stretch for 
more than 240 miles from Virginia Key on the north to the Dry Tor- 
tugas in the Gulf of Mexico, and present quite a range in climatic 
factors and vegetation. Many of them harbor an indigenous species, 
Cerion incanum (Binney), which, however, is quite unrelated to those 
that have been introduced. Furthermore, in selecting sites for our 
colonies v/e aimed to avoid placing the introduced forms where the 
native species existed. Colonies of 500 each were planted on the keys 
in 1912, as will be seen in the following pages. The shells of the mol- 
lusks planted were marked by two parallel file cuts made across two 
or more ribs. This method of marking has proved very satisfactory. 

Two Bahama species were planted in the first introduction. These 
are what are now termed Cerion casaUancce, a new species gathered in 
the neighborhood of the White House, which was our laboratory during 
the 1912 cruise, and which is situated between Sharp Rock Point and 
Driggs Hill, on the southeast side of South Bight, Andros Island. This 
species has been referred to in the previous reports as the White House 
type of Cerion. The material of the other species, which I am calling 
Cerion viaregis in the present paper, was gathered along King's Road, 
Bastion Point, on the northeast side of South Bight, Andros. The 
mollusks from this region have been referred to in the past reports as 
the King's Road type of Cerions. In addition to these two, 73 speci- 
mens of a small mottled Cerion (species ?) from Andros were planted 
on Bird Key. These have since disappeared without leaving any 
trace of progeny. They will therefore not be referred to again. 

An additional importation of 500 specimens of Cerion viareuis 
gathered in 1914 was planted on Loggerhaad Key (Colony F) on June 
9 of the same year. On the same date a second colony of mottled 
Cerions, Cerion (species ?), gathered at Spring Hill, Nassau, by Dr. 
Mayor in 1914, was made on Loggerhead Key. This colony has also 
disappeared, a few dead shells only remaining, so it also may be dis- 
regarded in our discussion. Our unfortunate experience with the 
painted Cerions in the Tortugas may indicate that this group does 
not find the environmental conditions suitable for its maintenance. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 5 

Another introduction was made on Loggerhead Key in 1915. This 
consisted of 800 specimens of Cerion crassilahris C'Shuttleworth" 
Sowerby) gathered by Dr. Mayor at Ballena Point, near Guanica Bay, 
Porto Rico. This will be referred to later as Colony L. 

The last introduction was made in 1916, and forms Colony N on 
Loggerhead Key. This colony consists of 8,317 specimens of Cerion 
uva (Linnaeus) gathered by Dr. Ralph Arnold at Curagao, Netherlands 
West Indies. 

Some of these colonies have now produced the second generation of 
Florida-grown offspring, and it is deemed desirable to put on record a 
complete account of the results so far attained in these breeding experi- 
ments. We shall consider in rotation the colonies of the different 
species from the north to the south, and give tables of measurements 
which will show the altitude and the greater and lesser diameter of the 
specimens. We will also give photographs of all the specimens meas- 
ured. The numbers given to the specimens measured will also be 
employed in the photographs, so that the two can readily be connected. 
It is deemed desirable to publish this large number of figures because 
the specimens discussed could not be retained as Museum records, for 
future observations, but had to be used for further breeding. Our 
photographs, therefore, must take the place of the specimen itself, and 
convey an idea of whatever variation in outline and sculpture the 
material grown in Florida may present. 

I have selected a larger check series (100 specimens) than in my 1915 
report, in which only 10 were used. This was deemed desirable in 
order to show more definitely the range of variations. This check 
series of 100 was taken at random from a large number of individuals 
and it is believed that it well represents all limits of variations. 

Cerions may be found on the ground, under the edges of stones, or 
on top of them, among dead leaves or upon blades of grass, dead 
stumps, the bases of trees, and on low bushes. They never ascend to 
any considerable height, for we have rarely found them beyond the 
reach of the hand above the surface of the ground. When Cerions 
occupy an exposed position they attach themselves to the support by a 
thin epiphragm which serves the double purpose of fixing them to the 
support and preventing desiccation; thus sealed up they appear to be 
able to estivate for a considerable length of time, and under such con- 
ditions are apparently not harmed, even when exposed to the blazing 
tropical sun for a prolonged period. 

Observations made during the years which have intervened between 
1912 and 1919 lead me to believe that Cerions are largely nocturnal. 
They are most active on misty nights. At such times the animals may 
be seen on the ground, where they dig, with about one-fourth to three- 
fourths of the animal and shell buried below the surface. Animals 



6 EXPERIMENTS IN THE BREEDING OF CERIONS. 

gathered at such times and examined prove to be filled with fungal 
mycelia, which evidently form a very large part of their food. The 
specimens kept in captivity, however, ha,ve shown a greater range of 
food selection ; paper seems to be particularly to their liking, although 
they will also feed upon moist cornmeal and other vegetable products; 
I feel quite certain, however, that in their natural environment their 
main diet is fungal. 

Unlike many other mollusks, instead of hiding away in moist, cool 
places with the approach of the dry, hot day, they leave their submerged 
position for a more elevated one, and thus placed they remain until 
the conditions are again favorable for another foraging expedition. 
When moving about they carry the shell almost horizontally sloping 
backward and pointing slightly to the right. 

Mating takes place on the ground. All the specimens which I have 
found in copulation were discovered in the early morning when the 
conditions of moisture were ideal for Cerion activities. The mating 
process is not a reciprocal one; that is, an animal is not actively male 
and female at the same time, but one functions as male and the other 
as female. The everted male organ is exceedingly long, attaining a 
length of fully an inch and a half when completely extended. WTien 
thus exposed, it reminds one strongly of a curved, flattened, white 
bristle. 

The eggs appear to be deposited at the base of tufts of grass beneath 
the surface of the ground and, judging from many gatherings of the 
young in such positions, one is led to believe that a single egg only is 
deposited at a time. I have never found more than 6 young Cerions 
(usually 1 to 4) at the base of a single small tuft of grass, and these 
always in different stages of growth, indicating rather long intervals 
betv/een oviposition. It is hoped that the experiments now in prog- 
ress in my conservatory will throw definite light upon this point. 

I have never found above ground young mollusks having the nepionic 
whorls only, and by far the larger number of those having attained 
three postnepionic whorls were dug from the sand about tufts of grass. 
It is only occasionally that one of this size seeks the characteristic 
elevated position of the parents. 

Our experiments have shown that it takes between 2 and 3 years to 
produce a new generation of Cerions. We may therefore consider this 
the time required for an individual to reach full maturity in its develop- 
ment. No definite data are at hand so far to determine the age which 
Cerions may attain, but many (probably most) of the specimens 
transplanted from the Bahamas in 1912 are still in good condition, 
if not destroyed by fire or crabs. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 7 

A COMPARATIVE ANATOMICAL DISCUSSION OF THE FIVE SPECIES 
OF CERIONS INVOLVED IN THE BREEDING EXPERIMENTS. 

It was deemed desirable that we should have some knowledge of the 
anatomical structures of the soft parts of the 5 species of Cerions which 
have been used in our breeding experiments. For that purpose a 
goodly number of specim.ens of each species was carried north this 
year, properly expanded, killed, decalcified, and the anatomical charac- 
ters subjected to close scrutiny. In the making of these dissections 
and drawings I have had the assistance of Dr. G. Dallas Hanna, one 
of my students and former associates. 

The 5 species in question are the native species, Cerion incanum 
(Binney); the specimens used for dissection came from Porgee Key; 
Cerion uva (Linnaeus) from Curagao; Cerion crassilahris ("Shuttle- 
worth" Sowerby) from Ballena Point, Guanica Bay, Porto Rico; 
Cerion casahlancce Bartsch from the White House region, Andros, to 
which we have referred as the "White House type Cerion" in the past 
reports, and Cerion viaregis Bartsch from the King's Road, Bastian 
Point, Andros, referred to in previous reports as the King's Road 
type Cerion. 

Externally no differences worthy of notice excepting shell characters 
were discovered in these 5 types. 

Tentacles and eye-stalks are developed in the manner of all Pul- 
monates. The locomotive disk, pedal groove, and caudal mucous 
pore are absent. The skin is covered with a series of white lines, of 
which those radiating from the mantle collar over the propodium and 
mesopodium are the most pronounced. These lines are crossed by 
connecting lines which produce an irregular reticulated pattern. 
The spaces inclosed in the meshes are dark gray to black on the top of 
the head, lighter on the sides and on the back of the foot. The genital 
opening is situated on the right side, beneath and slightly behind the 
eye-stalk; its orifice is not marked externally by a distinct structure 
or color pattern in the specimens examined. The breathing pore is 
opposite the posterior angle of the aperture of the shell. The anus and 
nephridiopore are on the right side and in contact with the breathing 
pore. 

The mouth is situated at the usual position, on the ventral side of 
the head. Immediately behind this is the broad opening to the pedal 
cavity. The pedal cavity narrows quickly and forms part of the 
inner floor of the body cavity as a membranous duct. 

The jaw is more or less strongly arched and provided with a median 
projection on the concave margin. The latter is scarcely perceptible 
in Cerion incanum and Cerion crassilahris, but is strongly marked in 
Cerion viaregis. No vertical m^arkings were noticed in any of the 
specimens examined and concentric lines when present are very faint. 



8 EXPERIMENTS IN THE BREEDING OF CERIONS. 

Cerion uva is stated by some writers to be without this median projec- 
tion, but the specimens examined did not agree with this dictum. 

The radula presents some interesting variations in the 5 species 
under consideration. The number of longitudinal tooth rows appears 
to be practically constant. Cerion uva has 20-1-20, Cerion viaregis 
22-1-22, Cerion crassilahris 23-1-23, Cerion casahlancce 25-1-25, 
Cerion incanum 27-1-27. These figures represent the rows which can 
be readily counted. The marginal teeth become mere plates at the 
extreme lateral margin, especially so in Cerion viaregis and Cerion 
crassilahris. These plates terminate as irregularly shaped masses 
which do not appear to be arranged in definite rows. It is therefore 
somewhat difficult to determine the exact number that can be actually 
counted in a given species, and this may account for slight differences 
reported for the same species by different observers. The markings 
on the marginal teeth can often not be made out with clearness ; they 
appear to be quadrangular, basal in most cases. There is a gradual 
transition from laterals into the marginal beginning with about the 
tenth tooth. The laterals are normally bifid with the inner cusp large 
and rounded and the outer one much smaller and also rounded, but in 
Cerion casahlancce the smaller one is absent, though a few of the transi- 
tional teeth, both laterals and marginals, show two cusps. The lateral 
teeth are uniformly about twice as long as wide and are placed slightly 
obliquely away from the rachidian tooth. The rachidian tooth presents 
considerable difference in the different species. In Cerion crassilahris 
there are three cusps, the central one appearing to be placed on a 
lower level than the outside cusps. This same condition seems to 
obtain in the laterals, the outer cusps being above the inner. In Cerion 
viaregis there is but a single large rounded central cusp. In Cerion 
casahlancce and Cerion incanum two minute projections are found 
bordering the median cusp. In Cerion uva the rachidian tooth is 
broader than long, while in all the other species it is about twice as 
long as broad. In this, too, the development of the lateral cusps is 
enormous. 

The buccal mass differs little from the usual structure in Pulmonates. 
The esophagus enters the top of the posterior portion. The two salivary 
ducts discharge on each side of the esophagus at the junction of the 
latter with the buccal cavity. The esophagus and the salivary ducts 
pass beneath the cerebral commissure and over the buccal commissure. 
The buccal ganglia are firmly attached to the buccal mass, one on each 
side of the esophagus. The radula sack v/ith the radula organ is 
situated just below the esophagus and projects backward from the 
distal end of the buccal mass. It extends from the radula sack, where it 
is attached, to the distal end of the buccal retractor, where it is inserted. 
In Cerion incanum the point of this insertion is in the center between 
the right and left branches of the buccal retractor, while in the other 



EXPERIMENTS IN THE BREEDING OF CERIONS. 9 

species examined it is inserted on its right branch. The buccal retractor 
(sometimes referred to as pharyngeal retractor) passes through the 
nerve ring above both the pedal and pleural ganglia, as does the 
esophagus, but it goes below the buccal commissure, whereas the 
esophagus passes above it. This muscle spreads out fan-shaped at its 
anterior end, where it is attached chiefly to the cartilaginous base of 
the buccal mass. It divides into two distinct parts before reaching 
the nerve ring or each branch may be further divided. In Cerion uva 
there are 4 branches on the left and 2 on the right, while in Cerion 
incanum and Cerion casablancce no definite divisions are found. In 
Cerion viaregis these divisions are very numerous and in Cerion cras- 
silabris 3 occur on the left side and 2 on the right. 

The salivary ducts are very short and lead from a distinctly paired 
gland. This gland covers the esophagus, to which it is firmly attached 
for a distance of 6 mm. At the posterior end of the salivary gland the 
esophagus is firmly attached to the buccal retractor muscle. The 
same relationship holds good in practically all the species examined. 

The esophagus becomes perceptibly constricted as it follows the 
several muscles backward into the visceral mass behind the saUvary 
glands. The anterior end of the stomach lies immediately behind the 
pericardium and kidney. The walls of the stomach are remarkable for 
their great length, narrowness, and thinness. The posterior end of the 
stomach lies high up in the whorls of the visceral mass and it is at this 
point tliat the two lobes of the hver discharge their secretion by dis- 
tinct ducts. The posterior lobe of the liver occupies the upper whorls 
of the shell, while the anterior lobe is distributed among the various 
organs below this. Both lobes are brownish-gray in color. The 
intestine forms a tube slightly larger than the esophagus and passes 
forward from the posterior end of the stomach. It makes the charac- 
teristic visceral loop back of the pulmonary cavity. In some of the 
species it is embedded in the albumen gland of the genital system, but 
in Cerion crassilahris and Cerion viaregis the albumen gland is free and 
the visceral lobe is rather imperfect. The intestine passes forward 
on the right side of the pulmonary cavity, to the dorsal wall of which 
it is firmly attached. In this region it is slightly larger than on the rest 
of its course and in Cerion incanum and Cerion crassilahris it appears 
to contain some glandular tissues in this region. The entire length of 
the alimentary tract amounts to about 85 mm. in Cerion incanum. 

The pulmonary cavity occupies more than one whorl of the shell 
when the animal is expanded. Its dorsal wall is thin, transparent, and 
unmarked excepting a scarcely perceptible pigmentation along the 
sides of the pulmonary vein. The pericardium and kidney are situated 
at the posterior end of the pulmonary cavity. The former is shorter 
than the kidney, but there is some variation in proportionate lengths. 
The auricle discharges into the pulmonary vein which passes forward 



10 EXPERIMENTS IN THE BREEDING OF CERIONS. 

to the mantle collar without perceptible branching in any of the 
species. The kidney lies just to the right of the pericardium and is 
somewhat pointed anteriorly. It appears as a hollow sack of light- 
grayish color, showing the glandular tissue hanging in irregular folds. 
The kidney is attached to the dorsal wall of the pulmonary cavity and 
the ureter, joining the latter at the posterior end. The ureter bends 
to the left as it passes forward, following the ventral side of the intestine 
to the nephridiopore, which is near the anus. 

Considerable difference is shown in the genitalia of the several species 
examined. Cerion incanum, Cerion casahlancce, and Cerion uva in the 
main agree with the description of Cerion munia chrysalis as described 
by Pilsbry in the Manual of Conchology. Cerion crassilahris and 
Cerion viaregis, however, are decidedly different. The terminal element 
of the system is formed by the atrium. This is broad and capacious in 
Cerion incanum and Cerion casahlancce, and less so in Cerion uva. In 
Cerion crassilahris and Cerion viaregis it is much larger and much more 
attenuated than in the rest. In Cerion incanum and Cerion casahlancce 
it is provided with a fleshy protuberance and some longitudinal folds 
which are evertible in copulation. 

The penis is attached to the right side of the atrium and differs 
considerably in shape and length in the species examined. In Cerion 
incanum and Cerion casahlancce it tapers to the upper end. In Cerion 
uva it is bulbous at the upper end, while in Cerion crassilahris its shape 
is more or less cylindrical. In Cerion viaregis it is larger at the upper 
end than in any of the other forms. The retractor muscle is attached 
to the upper end of the penis sack in every case and is inserted not 
far back on the floor of the pulmonary ca\'ity. In Cerion incanum and 
Cerion casahlancce the vas deferens is attached to the lower end of the 
penis. Its walls are densely muscular proximally, while distally it 
develops into a much coiled duct. The lower end has a silky appear- 
ance which seems to be due to the circular fibers in its structure. In 
Cerion uva the insertion of the vas deferens is at the upper end of the 
penis sack, while in Cerion crassilahris it is at about its center. These 
two species have the duct doubled back and attached to the vagina for 
its full length by muscle fibers. This is particularly so at the junction 
of the vagina Math the atrium. In Cerion viaregif" the vas deferens is 
attached to the upper end of the penis sack, but in a different manner 
than in the other forms examined. The attachment to the vagina in 
this form is less firm than in the others. (The figures of the genitalia 
in our plates show the organs disentangled in order to bring out details.) 
In Cerion incanum, Cerion casahlancce, and Cerion crassilahris the vas 
deferens is attached high up on the genital system, far above the 
attachment of the spermatic duct. In Cerion uva it is attached about 
halfway as high up on the vagina as it is in the species just mentioned, 
while in Cerion viaregis it enters the vagina far below the attachment 



EXPERIMENTS IN THE BREEDING OF CERIONS. 11 

of the spermatic duct. The vagina in all the species examined is 
attached to the left side of the atrium and is not clearly differentiated 
from the oviduct above; it is without folds. In Cerion incanum, Cerion 
casablanccE, Cerion uva, and Cerion crassilahris the spermatic duct 
enters the vagina slightly behind the atrium. In all of these it is largest 
at the lower end. This is most pronounced in Cerion incanum and 
least so in Cerion casablancce. In Cerion viaregis it is attached about 
halfway between the atrium and albumen gland. In Cerion incanum, 
Cerion casablancce, and Cerion uva the spermatic duct is long and 
slender and provided with a long flagellum near its upper fourth. This 
flagellum {diverticulum of Pilsbry) is exceedingly long in Cerion incanum 
and is shortest in Cerion uva. It is variously disposed among the 
viscera, but is not folded in any of the species examined. In Cerion 
incanum it follows the periphery of the whorls and its upper end is 
near the apex. This organ is entirely absent in Cerion crassilahris and 
Cerion viaregis. It has also been recorded absent in Cerion yumaense 
Pilsbry and Vanatta. The spermatic duct in all the species examined 
follows the vagina and oviduct, to w^hich it is closely adherent. The 
spermatheca may be globular or slightly elongated. In Cerion viaregis 
it is entirely absent. In this case it may be possible that what we have 
called the spermatic duct may in reality be the flagellum, the last 
remaining element of the spermatheca. 

The vagina is attached at the lower end to the right cephalic retractor 
muscle by a heavy band of muscle, w^hich is in two parts in Cerion 
incanum. The right ocular retractor is attached to the vagina at the 
same point in all but Cerion crassilahris, in which it connects directly 
with the cephalic retractor. The oviduct follows the columella of the 
shell and is thin and membranous on the periphery, and somewhat 
folded. The glandular tissue occupies a band along its inner margin. 
It contains gelatinous matter which swells and bursts the walls when 
the organ is placed in contact with water. These observations do not 
obtain in Cerion viaregis. In this form there is no apparent differentia- 
tion in structure between the vagina and oviduct. The former appears 
to continue unmodified to the albumen gland. The albumen gland is 
situated at the upper end of the oviduct and has the loop of the intes- 
tine coiled about it in all except Cerion crassilahris and Cerion viaregis, 
in which it is free. The hermaphroditic duct enters the concave mr.rgin 
of the albumen gland as a slightly convoluted tube and follows the 
columella of the shell upward to the hermaphroditic gland. In Cerion 
incanum, Cerion casablancce, Cerion uva, and Cerion crassilahris this 
duct is colored dark brown or black in its lowest portion. In Cerion 
crassilahris it is swollen in the lower part. In Cerion viaregis it is a 
simple straight duct without convolutions or pigment. The hermaph- 
roditic gland is embedded in the tissue of the upper lobe of the liver, 
to which it is firmly attached. The color of the two is the same and 



12 EXPERIMENTS IN THE BREEDING OF CERIONS. 

they are often difficult to distinguish. The organ is composed of a 
large number of minute tubules. 

There are four main muscle bands which follow the columella of the 
shell far up the interior to their place of attaclmient; these, in the order 
of their attachment, are : the columellar, right cephalic, buccal, and left 
cephalic muscles. The first spreads out in the tissue of the foot back 
of the opening to the buccal cavity. The right cephalic in Cerion 
incanum is attached to the shell with the columellar muscle. At its 
anterior end it is attached to the vagina and the right side of the head. 
The right tentacular retractor is attached to it. The right ocular 
retractor is also attached to it in Cerion crassilahris. The buccal 
retractor and left cephalic retractor are attached to the shell together 
and are placed slightly above the other two. The former has been 
described, the latter is attached to the left side of the head and the left 
tentacular and ocular retractors are attached to it. One right cephalic 
muscle in a well-expanded example of Cerion incanum was 12 mm. 
long. 

While there is a general similarity in the disposition of nerve struc- 
tures in all of the species examined, there is also some variation. The 
length of the cerebral commissure is not constant. In Cerion crassi- 
lahris and Cerion viaregis, the cerebral, pleural, and pleuro-pedal com- 
missures are perfectly distinct, while in the other species the first two 
elements are superficially attached through a portion of their length, 
the length of the commissure being so short that the ganglia are adja- 
cent. The esophageal ring is large and does not bind the esopliagus 
to the body floor, as in some mollusks. In a specimen of Cerion 
viaregis in which partial contraction had taken place, the buccal mass 
had been retracted through the ring. The structure of these elements, 
especially the cerebro-buccal commissure, would indicate that this 
was the normal state. The cerebral ganglia in normally expanded 
animals lie on top of the posterior portion of the buccal mass. The 
heavy connecting commissure passes over the salivary ducts and the 
esophagus. This is comparatively long in Cerion uva (Linnaeus) and 
practically absent in Cerion crassilahris. The shape and size of the two 
side cerebral ganglia is the same. 

There is a forward extension of the optic ganglion (best seen in side 
views), from which the optic nerve arises. Two nerves arise from the 
outer side of each ganglion. The upper one is the tentacular, while 
the lower one passes to the lip of the corresponding side. Both of 
these, as well as the optic nerve, terminate distally in enlargements 
which suggest ganglionic development. The cerebro-buccal commissure 
arises on the lower, inner, and anterior side of the cerebral ganglion. 
This is not free throughout its length, but becomes firmly bound to the 
buccal mass before it reaches the buccal ganghon. This condition 
seems to permit the buccal mass to retract through the nerve rinff 



EXPERIMENTS IN THE BREEDING OF CERIONS. 13 

Each buccal ganglion is situated adjacent to the attachment of the 
esophagus and the commissure passes beneath this over the buccal 
retractor muscle. The cerebro-pleural and pedal commissures arise 
on the ventral side of the cerebral ganglia. In some of the species 
they are united for a portion of their length, but in Cerion crassilahris 
and Cerion viaregis they are free throughout. The cerebral pleural 
commissure lies posterior to the pedal commissure. In some of the 
species nerves are found arising from the cerebral pleural commissures 
which pass to the right and left cephalic retractor muscles. 

The pleural elements are asynmietrical, a greater development being 
present on the left side. There are five ganglia in all, two on the right 
side and three on the left. From the upper two, pleural pedal com- 
missures pass forward to the pedal ganglia. In Cerion incanum, 
Cerion uva, and Cerion casahlancce these nerves are so short as to be 
scarcely discernible. The two true pleural ganglia are the largest of 
the series, the left being slightly the larger of the two. From the right 
one a large nerve arises and passes to the mantle collar, while two large 
nerves pass from the left to the floor of the pulmonary cavity. Between 
the left pleural and the upper pleural there is an extra ganglion which 
may correspond to the abdominal ganglion of certain other mollusks. 
At all events, it gives rise to a large nerve which passes to the viscera. 
The two pedal ganglia lie just in front of the pleural ganglia and are 
practically of equal size and shape. They join indirectly without a 
commissure. Numerous nerves pass from these to the tissues of the 
foot, especially in the anterior region. 

A very distinct blood-vessel passes between the pleural and pedal 
elements, which connects the base of the buccal mass with the wall of 
the mantle covering the visceral mass. It then passes backward beneath 
the pulmonary cavity, being free throughout most of its length. 

The great diversity in the anatomical structure of the five species 
of Cerions examined might tempt one to generalization, but I believe 
that it is w^ell to postpone this until a much larger series of species has 
been examined. It will then be easier to judge what values are to be 
assigned to the various structural differentiations observed in Cerions. 

THE COLONIES INTRODUCED INTO THE FLORIDA KEYS. 

We will take these up under the various species involved and discuss 
the colonies under each in serial rotation from north to south, i. e., 
from the Biscayne Bay region to the Dry Tortugas. 

Cerion viaregis Bartsch. 

Of this species, 100 specimens have been taken at random from a 
lot of Bahama material collected along King's Road, Bastian Point, 
Andros. These yield the measurements given in table 1 ; figures of them 



14 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



are given on plates 7, 8, 9. These specimens are entered as Cat. 
No. 234722, U. S. N. M., and No. 21 is selected to serve as the type 
of this species. 

Table No. 1. — Check series of Cerion viaregis. 







Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whoris. 


of shells. 


Serial 

No. 


No. of 
whoris. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


m,m. 


1 


10.5 


28.0 


12.7 


36 


9.6 


23.0 


11.0 


71 


9.8 


20.0 


11.1 


2 


10.3 


25.0 


11.5 


37 


10.0 


22.1 


10.0 


72 


10.0 


23.0 


11.9 


3 


10.0 


23.0 


12.1 


38 


9.8 


22.1 


11.0 


73 


9.9 


24.0 


11.0 


4 


9.7 


20.0 


9.1 


39 


10.0 


22.4 


11.5 


74 


11.0 


22.9 


10.0 


5 


9.9 


24.5 


11.0 


40 


10.7 


23.8 


11.0 


75 


10.0 


21.5 


11.0 


6 


9.1 


19.4 


9.0 


41 


9.9 


21.8 


11.5 


76 


10.5 


21.5 


11.0 


7 


10.8 


24.3 


11.3 


42 


9.9 


21.7 


11.0 


77 


9.9 


21.0 


10.4 


8 


10.8 


24.4 


12.0 


43 


9.9 


23.6 


11.0 


78 


11.0 


23.6 


11.0 


9 


11.0 


27.0 


12.0 


44 


9.8 


22.5 


11.0 


79 


10.0 


21.0 


11.4 


10 


10.4 


24.5 


13.5 


45 


10.3 


24.5 


11.5 


80 


10.0 


22.0 


11.0 


11 


9.3 


20.5 


11.0 


46 


10.5 


22.8 


11.4 


81 


10.0 


22.7 


11.4 


12 


10.5 


23.8 


12.0 


47 


10.3 


22.7 


11.1 


82 


9.8 


21.3 


10.5 


13 


10.6 


22.7 


11.0 


48 


10.5 


24.0 


11.8 


83 


9.7 


21.5 


11.0 


14 


10.0 


23.0 


11.0 


49 


9.9 


19.0 


11.0 


84 


9.9 


21.8 


11.0 


15 


10.1 


24.4 


12.0 


50 


10.6 


23.9 


11.0 


85 


9.6 


21.0 


11.0 


16 


9.9 


22.0 


12.0 


51 


9.6 


22.0 


11.8 


86 


10.5 


22.2 


12.0 


17 


10.4 


24.0 


11.0 


52 


10.0 


22.5 


10.5 


87 


9.8 


21.1 


10.9 


18 


10.0 


22.5 


10.5 


53 


9.0 


24.0 


10.5 


88 


9.6 


20.0 


11.0 


19 


11.0 


25.5 


11.2 


54 


10.2 


23.0 


11.5 


89 


9.6 


20.5 


9.4 


20 


9.0 


23.0 


12.0 


55 


10.5 


22.8 


12.0 


90 


9.8 


21.5 


10.5 


21 


10.0 


22.9 


11.0 


56 


10.0 


20.3 


10.5 


91 


10.3 


23.2 


10.5 


22 


10.0 


22.8 


10.5 


57 


9.3 


22.0 


11.0 


92 


10.2 


25.0 


11.5 


23 


10.4 


24.0 


11.0 


58 


10.2 


24.1 


11.0 


93 


10.4 


23.2 


11.6 


24 


10.1 


23.9 


12.0 


59 


9.7 


20.8 


10.8 


94 


9.8 


21.8 


10.9 


25 


10.4 


24.5 


12.2 


60 


10.0 


21.5 


11.5 


95 


10.1 


21.1 


10.2 


26 


10.4 


24.5 


12.0 


61 


10.0 


21.5 


11.2 


96 


10.6 


23.0 


11.1 


27 


9.8 


22.5 


11.4 


62 


9.6 


21.5 


11.4 


97 


10.8 


23.6 


11.1 


28 


9.9 


24.0 


11.5 


63 


9.7 


21.4 


10.9 


98 


10.2 


20.0 


10.0 


29 


11.0 


21.6 


9.5 


64 


9.8 


21.5 


11.5 


99 


10.4 


21.5 


10.5 


30 


9.9 


23.5 


11.9 


65 


10.0 


22.8 


9.5 


100 


10.3 


21.3 


10.3 


31 


10.6 


23 4 


12.4 
11.5 


66 
67 


10.0 
10.6 


22.0 
22.0 


11.5 
11.5 










32 


10.6 


24.0 


Average . 


10.08 


22.56 


11.13 


33 


8.8 


19.0 


10.5 


68 


9.6 


21.5 


12.0 


Greatest. 


11.0 


27.0 


12.7 


34 


9.9 


21.0 


12.0 


69 


9.5 


21.5 


10.5 


Least . . . 


9.1 


19.0 


9.0 


35 


10.6 


23.5 


11.0 


70 


10.0 


23.0 


11.5 











The Colony on the Second R.\gged Key North of Sands Key. 

The northernmost colony is situated on the Second Ragged Key 
north of Sands Key. Here 500 of Cerion viaregis were planted on a low 
sandy ridge on the southeastern end of this small island in 1912. The 
vegetation at this point is quite variable. Hymenocallis (commonly 
called Amarillis in this general region) forms the most succulent portion 
of the plant element, while Sporohulus virginicus and Gayoides imherhe 
and a few scattered, shrubby plants furnish a scant covering for quite 
a stretch of beach sand. The outer and inner edge of the dune is 
fringed with a mangrove thicket. There is hkewise a lot of piled-up 
sea drift in places. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



15 



Our visit in 1913 showed that our Cerions had spread over all the 
above-described territory. 

On April 21, 1914, we again visited this plantation and found 55 
young of the first generation of Florida-grown individuals, 3 of which 
had attained adult size; these we figured in the 1915 report, plate iii, 
figures 1 to 3, bottom row. They are discussed in the text. We trans- 
planted these to a grassy spot about 62 feet northeast of the old 
plantation on the same key. 

From this colony 76 adult shells of the first generation of Florida- 
grown specimens were gathered in June 1915, measured, and photo- 
graphed. The measurements are given in table 2 and the photographs 
on plates 10 and 11. 



Table No. 2.— 


Measurements of the first generatio 


<i of Florida-grown 


Cerion 


viaregis 










from the second key north of Sands Key. 










Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm,. 


mm. 






mm. 


mm. 


1 


10.0 


21.9 


10.6 


28 


10.0 


20.9 


10.5 


55 


9.5 


21.0 


10.2 


2 


10.5 


24.9 


11.1 


29 


9.5 


21.7 


10.3 


56 


11.0 


24.9 


10.4 


3 


10.3 


22.5 


11.1 


30 


10.1 


25.2 


10.7 


57 


10.7 


25.8 


10.6 


4 


10.0 


22.7 


11.0 


31 


10.0 


23.0 


10.7 


58 


9.7 


23.8 


11.0 


5 


9.9 


22.0 


9.5 


32 


9.8 


22.9 


10.0 


59 


10.6 


24.9 


10.7 


6 


10,0 


22.8 


10.8 


33 


10.5 


23.1 


10.0 


60 


9.7 


22.0 


10.6 


7 


10.5 


23.2 


10.8 


34 


10.4 


23.8 


10.2 


61 


9.7 


22.5 


10.4 


8 


10.5 


24.0 


11.0 


35 


10.4 


23.7 


10.0 


62 


9.6 


22.0 


10.0 


9 


10.0 


23.7 


9.9 


36 


10.0 


23.4 


10.2 


63 


10.6 


24.0 


11.2 


10 


10.0 


21.5 


10.0 


37 


9.9 


22.3 


10.3 


64 


9.6 


22.5 


11.2 


11 


10.1 


23.3 


10.0 


38 


10.4 


23.0 


10.0 


65 


9.4 


20.0 


10.7 


12 


10.1 


23.8 


10.2 


39 


10.4 


24.4 


10.5 


66 


10.0 


23.5 


10.6 


13 


10.5 


24.5 


10.0 


40 


10.5 


24.0 


10.0 


67 


10.2 


21.8 


10.3 


14 


10.5 


23.8 


9.5 


41 


10.4 


22.8 


10.2 


68 


10.1 


22.7 


10.0 


15 


8.9 


19.2 


9.9 


42 


10.3 


23.5 


10.5 


69 


10.1 


22.9 


10.0 


16 


10.0 


24.9 


10.3 


43 


10.3 


23.3 


10.3 


70 


9.4 


21.8 


10.4 


17 


9.8 


21.5 


10.0 


44 


9.5 


21.0 


10.0 


71 


10.0 


23.9 


11.2 


18 


9.8 


21.6 


10.0 


45 


9.7 


22.0 


10.2 


72 


10.6 


24.0 


10.0 


19 


10.5 


25.0 


10.1 


46 


10.3 


22.2 


10.6 


73 


10.0 


22.5 


10.0 


20 


9.6 


22.3 


10.1 


47 


9.1 


20.0 


10.5 


74 


9.5 


21.5 


10.0 


21 


9.6 


21.9 


10.0 


48 


10.3 


22.8 


10.5 


75 


9.8 


19.5 


11.0 


22 


10.1 


22.5 


10.0 


49 


10.0 


23.1 


11.4 


76 


9.7 


22.6 


11.3 


23 
24 


10.0 
9.7 


23.0 
21.2 


10.8 
10.3 


50 
51 


9.9 
10.3 


22.5 

23.8 


10.0 
10.6 










Average . 


10.03 


22.82 


10.4 


25 


10.1 


24.0 


10.5 


52 


10.2 


23.8 


10.5 


Greatest. 


11.0 


25.8 


11.4 


26 


9.6 


21.5 


10.1 


53 


10.1 


22.5 


11.0 


Least . . . 


8.9 


19.2 


9.5 


27 


9.9 


23.9 


10.7 


54 


10.1 


22.7 


10.9 











On May 16, 1916, the old planting was doing well. Old and young 
were up in the vegetation. The old colony occupied almost the same 
extent of territory that it held the year before. The two other plantings 
were all doing well. 

The planting was not visited in 1917 or 1918. In January 1919, 
we again examined it and found the first planting flourishing. In 
the new plantings, however, we did not find the mollusks abundant, 



16 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



but we secured 8 individuals belonging to the second generation of 
Florida-grown specimens, of which table 3 gives measurements. They 
are figured on plate 24, middle set of figures. 

Table No, 3. — Measurements of the second generation of Florida-grown Cerion viaregis 
from the second key north of Sands Key. 



Serial 
No. 


No. of 
whorls. 


Measurements 
of shells. 


Serial 
No. 


No. of 
whorls. 


Measurements 
of shells. 


Summary. 


No. of 
whorls. 


Measurements 
of shells. 


Ait. 


Diam. 


Alt. 


Diam. 


Alt. 


Diam. 


1 
2 
3 
4 


10.0 
10.5 

10.3 
11.1 


mm. 

22.6 

23.0 

24.2 
26.4 


mm. 

11.2 

10.2 

11.0 

11.3 


5 
6 

7 
8 


10.1 

10.0 

9.6 

10.1 


mm. 

23.4 

21.8 

21.0 

21.2 


m7n. 

11.1 

11.0 

10.7 

10.5 


Average . 
Greatest. 
Least. . . 


10.21 

11.1 

9.6 


m7n. 
22.95 
24.2 
21.0 


mm. 
10.87 
11.3 
10.2 



The CoLoisrY on Tea Table Key. 

On June 1, 1912, we planted 500 specimens of Cerion viaregis on Tea 
Table Key. These were scattered about the ruins of an old house on 
the north side of the island. The ground seemed ideal, coarse calcare- 
ous beach sand supporting a scanty scattered herbaceous vegetation. 
When we visited the place on April 27, 1913, where the planting 
had been made, we found it covered with a rank growth of a mal- 
vaceous plant which seemed to be unsuited to the Cerions, for they 
had all left it and wandered inland, some as much as 100 feet. Most 
of them expired on this journey, for of the 75 recovered, only 3 were 
alive; these we placed in a clump of Hymenocallis, about 200 feet 
northwest of a cordia tree, which is about 100 feet west of the old build- 
ing where the first planting v/as made. The aspect of the place where 
the original planting was made seemed very favorable for Cerions 
last year, for the malvaceous plants had died and shed their foliage 
after fruiting. 

Our visit on April 22, 1914, showed no living Cerion. At that time 
the island was completely overrun vaih. crabs, the entire land mass 
being simply riddled with theu' burrows. It is quite possible that the 
small hermit crabs which were also swarming on this key at the time 
may have carried off the dead shells. 

It seems safe to assume that the colony on this key is extinct, as our 
visits in 1915, 1916, 1917, and 1919 showed no trace of Cerions, and in 
January 1919 the greater part of the key was covered by a tomato 
plantation. 

The Colony on Duck Key. 

On June 2, 1912, a planting of 500 specimens of Cerion viaregis was 
made on the south side of Duck Key. At that time the key was 
covered by a scattered growth of Uniola paniculata. On our visit on 
April 28, 1913, this colony was doing well. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 17 

All visits during subsequent years have shown that this little island 
has become so completely swamped with grass that it has been impossi- 
ble to determine whether Cerions have survived in large numbers or 
whether they are multiplying. Occasionally a young tip has been 
seen, and in 1916 we found one young locally grown specimen. It has 
therefore been impossible to gain material representing the first and 
second generations. Not until some time in the future, when drought 
or some other condition will have overcome the rank grass, will it be 
possible to determine the true status of this colony. 

The Colony on Newfound Harbor Key. 

On June 3, 1912, in a low grassy plain in the middle of Newfound 
Harbor Key, 500 specimens of Cerion viaregis were planted. When 
visited on April 28, 1913, the place had become densely matted with a 
luxuriant growth of grass, Sporohclus virginicus, and was quite moist ; 
apparently the low depression in the middle ha.d been flooded by some 
storm. Fearing that a more serious inundation might kill the members 
of this colony, a new place was selected for the 145 specimens recovered, 
of which 14 were dead. The 131 living specimens were carried inland 
to the sandy ridge, where they were placed between the coconut trees. 
The tree near which the planting was made was marked by a double 
cross cut in its trunk. 

On April 23, 1914, we again visited Newfound Harbor Key and 
found that the place of the second planting was swamped with a dense 
growth of a malvaceous plant, overgrown with a leguminous climber, 
indicating that a very poor choice of location had been made for this 
planting last year. 

In 1915 this colony was not examined. 

On May 22, 1916, the ground where the second planting was made 
had been completely burned over; only a single specimen of the orig- 
inally planted material and one locally grown individual were found; 
but in the low flat where the first planting was made, we found 51 
individuals which represent the first generation of the Florida-grown 
specimens and 3 of the original planting. Among these were 4 shells 
of hybrids between Cerion viaregis and the native Cerion incanum. 
These were on bushes which carried both introduced and local forms. 

It should be stated that at our first planting on this key, in 1912, 
no native Cerions appeared. 

In 1917 and 1918 this colony was not visited, but on January 19, 
1919, when we revisited the place, the Cerion colony in the middle of 
the plain was doing well. Numerous individuals were present every- 
where, but most of the individuals were hybrids between Cerion 
incanum (Binney) and Cerion viaregis. We gathered a goodly quantity 
of these, which were taken to Washington and placed in a conservatory 
for continued close observation and possible selective breeding. The 



18 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



details presented by this material will be discussed at another place 
in this report. The second plantation on the ridge seemed to have 
recovered from the effects of the fire, but only a few specimens of the 
King's Road type were there, and absolutely no trace of an admixture 
with Cerion incanum was shown in any of the specimens. 

The Colony on Boca Grande Key. 

On June 8, 1912, we planted 500 specimens of Cerion viaregis beneath 
the U. S. Coast Survey beacon on the northwest end of Boca Grande 
Key. The ground at this place is the usual coarse-grained calcareous 
sand supporting a rather luxuriant growth of Uniola paniculata. This 
colony was doing well on May 1, 1913. 

Table No. 4. — Measurements of the first generation of Florida-grown Cerion viaregis 

from Boca Grande Key. 







Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 


No. of 


of shells. 










No. 


whorls. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


m?n. 






7nm. 


mm. 


1 


10.9 


24.8 


11.0 


38 


10.3 


25.3 


11.0 


75 


10.0 


22.2 


10.1 


2 


10.7 


24.2 


10.9 


39 


9.8 


21.9 


10.1 


76 


10.5 


24.0 


11.2 


3 


10.1 


23.4 


10.7 


40 


10.9 


27.1 


11.2 


77 


10.3 


23.5 


11.0 


4 


11.0 


26.5 


10.0 


41 


10.3 


21.8 


10.0 


78 


9.9 


22.6 


9.0 


5 


10.2 


25.5 


11.2 


42 


9.1 


21.0 


10.3 


79 


9.8 


23.1 


10.0 


6 


10.4 


25.4 


11.4 


43 


9.7 


21.7 


10.0 


80 


9.9 


21.9 


10.1 


7 


10.2 


23.1 


10.3 


44 


11.1 


25.8 


9.6 


81 


10.2 


24.2 


11.0 


8 


10.3 


22.6 


10.5 


45 


10.9 


23.2 


11.0 


82 


10.3 


21.6 


10.1 


9 


10.2 


24.1 


10.8 


46 


10.7 


24.9 


11.4 


83 


10.4 


24.1 


10.2 


10 


10.3 


22.2 


9.9 


47 


10.3 


23.6 


10.5 


84 


10.4 


23.7 


10.0 


11 


10.4 


23.5 


10.4 


48 


10.1 


24.0 


10.5 


85 


10.3 


23.9 


10.3 


12 


10.4 


24.2 


11.3 


49 


10.9 


25.8 


10.2 


86 


10.3 


24.5 


10.5 


13. 


10.8 


23.4 


10.0 


50 


10.3 


23.5 


11.5 


87 


10.9 


24.2 


10.5 


14 


10.2 


23.7 


11.0 


51 


9.7 


21.5 


10.4 


88 


10.6 


23.0 


10.0 


15 


10.1 


22.5 


11.3 


52 


9.9 


23.0 


10.7 


89 


10.6 


26.0 


11.6 


16 


10.5 


25.0 


10.5 


53 


10.6 


24.7 


10.5 


90 


9.9 


22.0 


9.9 


17 


10.1 


23.4 


10.2 


54 


10.9 


25.2 


10.5 


91 


10.4 


24.0 


11.4 


18 


10.4 


22.2 


10.5 


55 


10.3 


24.0 


9.8 


92 


10.4 


22.9 


10.8 


19 


9.5 


21.4 


10.4 


56 


10.7 


24.7 


9.9 


93 


10.3 


23.5 


10.2 


20 


10.7 


24.8 


10.0 


57 


10.1 


24.7 


10.9 


94 


10.3 


23.0 


11.1 


21 


10.0 


21.6 


10.2 


58 


10.8 


24.6 


10.1 


95 


11.1 


23.7 


11.0 


22 


9.9 


22.0 


10.0 


59 


10.2 


22.7 


10.6 


96 


10.6 


25.5 


11.5 


23 


10.0 


23.5 


10.8 


60 


10.6 


26.4 


11.0 


97 


10.2 


23.0 


10.6 


24 


10.6 


23.7 


11.0 


61 


11.1 


26.3 


11.4 


98 


10.7 


25.8 


11.3 


25 


9.9 


21.9 


9.7 


62 


10.4 


23.7 


9.6 


99 


10.7 


24.5 


10.0 


26 


10.9 


26.5 


10.7 


63 


10.9 


26.2 


10.6 


100 


9.8 


21.3 


10.0 


27 


10.0 


21.0 


9.7 


64 


10.5 


23.9 


10.4 


101 


9.8 


20.9 


11.0 


28 


10.1 


23.5 


10.9 


65 


10.5 


24.1 


9.7 


102 


9.8 


21.0 


9.9 


29 


9.8 


23.0 


11.0 


66 


9.6 


22.0 


9.6 


103 


10.8 


23.7 


10.9 


30 


10.3 


22.5 


10.3 


67 


10.6 


24.7 


10.4 


104 


11.2 


26.9 


11.6 


31 


9.5 


20.2 


10.6 


68 


10.2 


25.2 


10.7 


105 


9.7 


23.0 


10.4 


32 


9.6 


21.7 


10.2 


69 


9.9 


22.0 


10.5 


106 


10.3 


21.7 


9.6 


33 


10.5 


24.5 


10.0 


70 


9.7 


20.6 


10.5 


107 


10.3 


21.8 


9.4 


34 


10.9 


26.8 


10.1 


71 


10.5 


25.7 


10.7 
9.7 










35 


9.7 


22.8 


9.9 


72 


9.9 


21.0 


Average . 


10.31 


23.57 


10.46 


36 


9.9 


23.3 


10.6 


73 


10.2 


22.7 


9.9 


Greatest. 


11.2 


27.1 


11.6 


37 


10.3 


22.4 


10.0 


74 


10.5 


25.1 


10.0 


Least. . . 


9.1 


20.2 


9.0 



EXPERIMENTS IN THE BREEDING OF CERIONS. 19 

On April 29, 1914, it was discovered that the grass had been burned 
about the beacon and that most of our specimens had been roasted. 
Quite a number of young, however, were present in the tufts of grass 
not consumed by fire, and 3 adults and 1 nearly grown of the first 
Florida-grown generation were found. These are illustrated by the 
last four figures of the bottom row on plate 3 of the 1915 report. 

On June 25, 1915, we again visited Boca Grande Key and collected 
119 specimens of the first generation of Florida-grown Cerions; 107 of 
the adult specim^ens and 9 of the young, after being marked, measured, 
and photographed, were replanted on this key about 300 feet south of 
the beacon, a little nearer the bushes than the shore. A Tournefortia 
bush standing on the edge of the shore marks the intersecting line 
opposite which the planting was made. The measurements of these 
appear in table 4, and for the figures see plates 12, 13, 14. 

On June 4, 1916, when we again visited Boca Grande, the beach had 
been burned over and our second planting, consisting of the first 
generation of Florida-grown individuals, seemed completely destroyed. 
In the original planting, however, a few shells were seen on the grass 
{Uniola paniculata) about the beacon and many more were observed 
in a little meadow of Sporoholus virginicus, which is separated from the 
outer beach by a fringe of low bushes. It is possible that this remnant 
of the colony may rehabilitate this planting. 

On July 18, 1917, on revisiting Boca Grande, the colony in the little 
meadow immediately inside of the fringe of bay cedars near the beacon 
appeared to be doing well, but no shells were found in the location of 
the second planting. 

On January 6, 1919, we reexamined the planting on Boca Grande 
and found a few mollusks about the beacon and a goodly number in 
the little meadow within the fringe of bay cedars, where they had 
spread for fully 100 feet. No trace of the planting of the first genera- 
tion of Florida-grown individuals had appeared, and since it is impossi- 
ble to tell whether the specimens about the beacon belong to the first 
or second generation, no attempt will be made to utilize them in our 
discussion. Our experiments for the time being, therefore, have ceased 
so far as this colony is concerned, and the only further interest that 
they present will be to see what changes, if any, may occur. 

The Colony on Garden Key, Tortugas. 

On June 8, 1912, a planting of 138 specimens of Cerion viaregis was 
made back of a small house on the northeast side of the fort on 
Garden Key. This planting was visited on May 2, 1913. At this time 
the place, which is a beach of coarse calcareous sand, was occupied by 
a sparse growth of Sporoholus virginicus and Uniola paniculata and a 
rank growth of the goatfoot morning-glory, Ipomcea pes-caprae. I 
cleared a space of 10 by 20 feet by the use of a pocket knife and recov- 



20 EXPERIMENTS IN THE BREEDING OF CERIONS. 

ered 60 of the planted mollusks. I was told that some visitor had 
discovered this colony and collected some of the specimens, promising 
to replace them, but it is not absolutely known whether this had been 
done. A single young specimen was also discovered at this time, which 
showed that they were breeding. The place being deemed unsuitable 
for the colony, the 62 specimens were transplanted to the inside of the 
fort near the center, where conditions appeared to be much more 
favorable than in the place first selected. As the fort was about to be 
abandoned, little fear of interference mth this colony was expected. 

The Garden Key plantings were examined on April 27, 1914, when it 
was discovered that the second planting inside of the fort had been 
completely burned over; 28 dead shells were found, but the rest had 
disappeared. A visit to the original planting showed 6 living specimens 
of the original planting, but no young. The place was less overgrown 
this year than the last. Apparently the cleaning up to which I sub- 
jected it then had decreased the morning-glory growth and this gave 
the Cerions a better chance. We left the 6 specimens in a tuft of grass 
in this place. 

In 1915 no specimens were found in this planting, and in 1916 only a 
single individual. In neither of these years was there a single trace of 
Cerions seen on the inside of the fort. 

In 1917 and 1918 this planting was not visited, but on January 16, 
1919, a careful search was made both within and without the fort, but 
not a trace of Cerions was discovered, so it is to be feared that this 
colony has disappeared. 

The Colonies on Loggerhead Key, Tortogas. 

On this key 10 plantings of Cerion viaregis have been made. They 
bear the letters E, F, G, H, I, K, M, P, Q, and R, and were established 
in the order listed. We shall discuss them now in this sequence. 

The Loggerhead Key Colony E. 

On June 8, 1912, in a sandy plain covered by a mixed stand of 
Uniola paniculata and Sporoholus virginicus, 500 specimens of Cerion 
viaregis were planted near the south end of the island. The place was 
marked by a stake. 

In May 1913 a large number of young were observed, 55 of which 
were gathered in 20 minutes in a space of 3 square yards. The young 
were all about the base of tussocks of grass, some on and some under 
the surface of the ground. 

In April 1914 we gathered 300 young specimens (some of which were 
figured in the 1915 report, upper figure of plate 5) and 3 full-grown and 
3 nearly full-grown individuals (see top row of plate 3 of 1915 report). 
The young were planted in a small meadow to the northeast of the one 
in which the present colony is planted. They were marked with a tag 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



21 



affixed to a stake bearing the legend ''Cerions Z." These represent 
the initital planting of Colony G. The variations presented by the 
adult specimens are discussed in the 1915 report. 

On June 27, 1915, we found that this colony had spread materially 
and that many of the snails had taken to the bay cedars bordering the 
little meadow. Of the first generation of Florida-grown specimens 
646 M^ere gathered, 250 of which were photographed and measured. 
For measurements see table 5, and for the photographs see plates 15-21. 
These were marked and deposited in the north end of the meadow and 
the place marked by a stake and a tag bearing the legend: "Cerions, 
1915, K." These represent the initital planting of Colony K. 





Table No. 5.— 


-First generation of Florida 


-grown Cerion viaregis from 


Colony E. 








Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whoi'ls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


-mm. 






mm. 


WW. 






WW. 


WW. 


1 


9.8 


22.8 


10.1 


42 


10.0 


24.5 


10.4 


83 


9.7 


23.6 


10.3 


2 


10.2 


23.2 


10.6 


43 


10.4 


22.5 


9.5 


84 


10.5 


24.0 


10.6 


3 


10.0 


21.6 


10.5 


44 


10.6 


22.5 


9.1 


85 


10.3 


24.4 


9.5 


4 


10.5 


24.0 


9.6 


45 


10.1 


22.3 


10.0 


86 


9.5 


19.8 


9.3 


5 


10.9 


24.1 


9.8 


46 


10.6 


22.0 


9.9 


87 


9.4 


20.5 


10.3 


6 


10.2 


23.5 


10.0 


47 


9.5 


20.6 


10.2 


88 


10.8 


25.5 


10.4 


7 


10.2 


24.0 


10.2 


48 


10.6 


26.0 


9.2 


89 


10.4 


23.0 


10.5 


8 


9.6 


22.7 


10.3 


49 


10.3 


23.0 


10.5 


90 


9.8 


20.8 


9.0 


9 


10.3 


23.0 


10.9 


50 


10.3 


21.8 


9.6 


91 


10.0 


22.8 


11.0 


10 


11.1 


25.4 


9.8 


51 


10.4 


23.0 


9.4 


92 


9.8 


22.7 


10.1 


11 


10.2 


24.6 


9.1 


52 


9.6 


21.2 


10.0 


93 


10.0 


20.0 


10.1 


12 


9.9 


22.0 


9.6 


53 


11.2 


26.7 


10.8 


94 


9.4 


20.0 


10.2 


13 


10.7 


24.5 


10.2 


54 


9.8 


23.0 


10.2 


95 


10.3 


22.5 


9.7 


14 


9.7 


20.9 


9.5 


55 


10.5 


22.2 


10.2 


96 


9.7 


21.6 


9.7 


15 


10.2 


23.7 


10.4 


56 


9.7 


22.4 


9.7 


97 


10.3 


24.3 


10.0 


16 


9.3 


20.6 


10.5 


57 


10.2 


21.7 


10.1 


98 


9.9 


21.5 


10.2 


17 


10.2 


22.7 


9.8 


58 


10.0 


22.2 


10.1 


99 


9.7 


21.5 


10.8 


18 


10.2 


22.5 


11.2 


59 


10.4 


23.0 


10.2 


100 


10.5 


23.3 


10.3 


19 


10.4 


24.0 


10.4 


60 


11.0 


24.8 


10.3 


101 


10.1 


23.0 


9.5 


20 


10.4 


23.4 


10.6 


61 


9.5 


21.6 


9.4 


102 


10.2 


22.4 


9.9 


21 


10.5 


24.1 


9.6 


62 


10.3 


23.4 


10.1 


103 


10.3 


23.5 


10.4 


22 


10.4 


23.3 


10.1 


63 


10.2 


22.5 


10.0 


104 


9.5 


22.5 


10.6 


23 


11.7 


27.9 


9.7 


64 


9.5 


20.8 


9.6 


105 


10.0 


22.3 


9.7 


24 


10.4 


23.2 


9.6 


65 


10.2 


22.4 


9.8 


106 


9.6 


20.9 


9.8 


25 


9.7 


22.3 


10.0 


66 


10.5 


24.0 


10.2 


107 


10.2 


21.0 


10.3 


26 


10.1 


21.3 


11.2 


67 


9.6 


21.1 


10.0 


108 


10.0 


24.8 


11.1 


27 


10.2 


23.4 


10.4 


68 


9.4 


18.7 


9.5 


109 


9.9 


22.5 


10.2 


28 


9.1 


18.7 


9.8 


69 


10.1 


21.1 


10.0 


110 


9.6 


20.5 


9.6 


29 


10.3 


23.5 


10.4 


70 


10.4 


23.5 


9.6 


111 


9.6 


24.0 


11.4 


30 


10.2 


24.3 


11.0 


71 


9.9 


21.9 


9.6 


112 


9.6 


21.0 


9.5 


31 


10.4 


22.7 


9.3 


72 


10.3 


22.2 


9.5 


113 


9.8 


23.4 


10.3 


32 


9.2 


20.0 


10.0 


73 


10.6 


23.5 


9.9 


114 


9.7 


22.2 


10.3 


33 


10.0 


21.5 


9.8 


74 


9.7 


21.3 


9.5 


115 


10.0 


21.5 


10.0 


34 


10.3 


23.7 


10.2 


75 


10.2 


22.5 


10.2 


116 


9.6 


21.6 


10.2 


35 


10.3 


25.3 


10.4 


76 


9.7 


21.8 


10.7 


117 


10.3 


23.0 


10.0 


36 


10.0 


22.4 


9.7 


77 


10.0 


24.7 


10.9 


118 


10.1 


21.8 


9.4 


37 


9.7 


19.7 


9.5 


78 


10.6 


24.6 


9.6 


119 


10.0 


22.4 


9.9 


38 


10.8 


23.2 


9.8 


79 


9.4 


20.6 


10.2 


120 


10.5 


23.0 


9.5 


39 


9.7 


21.2 


10.5 


80 


9.5 


20.1 


10.0 


121 


9.4 


20.0 


10.0 


40 


10.1 


22.1 


10.7 


81 


9.8 


22.3 


10.9 


122 


10.5 


20.2 


9.0 


41 


9.8 


21.8 


10.3 


82 


9.8 


22.3 


10.5 


123 


10.1 


22.7 


10.0 



22 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



Table No. 


5 — First generation of Florida-grown 


, Cerion 


viaregisfrom Colony E — continued. 








Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 


No. of 


of shells. 










No. 


whorls. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mTJi. 


mm. 






mm. 


min. 






77im. 


mm. 


124 


10.2 


24.5 


9.4 


168 


10.0 


24.0 


10.4 


212 


10.2 


22.0 


9.5 


125 


9.3 


19.7 


10.3 


169 


9.5 


20.7 


9.8 


213 


9.5 


21.5 


9.8 


126 


9.6 


21.9 


9.5 


170 


10.1 


24.1 


10.3 


214 


10.0 


23.1 


10.5 


127 


10.2 


23.2 


10.2 


171 


10.0 


22.6 


9.7 


215 


9.8 


21.3 


9.7 


128 


10.5 


24.4 


9.6 


172 


12.0 


21.7 


9.9 


216 


10.8 


25.3 


10.0 


129 


10.0 


22.1 


10.3 


173 


10.0 


23.2 


10.0 


217 


10.0 


23.4 


10.1 


130 


9.2 


19.6 


9.5 


174 


9.7 


20.9 


9.4 


218 


10.3 


23.3 


10.6 


131 


10.0 


22.4 


10.5 


175 


10.7 


25.5 


10.0 


219 


10.0 


22.1 


9.9 


132 


10.2 


23.2 


9.6 


176 


9.1 


20.0 


10.2 


220 


9.7 


21.1 


9.9 


133 


10.2 


23.5 


10.7 


177 


9.7 


21.5 


9.6 


221 


10.1 


23.7 


10.6 


134 


10.0 


22.3 


9.8 


178 


9.7 


20.7 


9.5 


222 


10.0 


23.8 


11.2 


135 


10.9 


26.4 


9.9 


179 


10.3 


24.0 


9.2 


223 


9.7 


20.5 


10.0 


136 


9.6 


20.5 


10.0 


180 


10.3 


22.1 


9.6 


224 


9.5 


22.2 


11.0 


137 


11.3 


24.7 


9.1 


181 


10.2 


23.9 


9.9 


225 


10.4 


21.3 


10.0 


138 


10.5 


23.0 


10.0 


182 


9.6 


20.7 


10.0 


226 


10.4 


22.5 


10.0 


139 


10.0 


21.7 


10.1 


183 


10.1 


23.0 


11.0 


227 


9.4 


19.8 


10.3 


140 


10.6 


23.6 


10.0 


184 


10.0 


23.2 


10.5 


228 


9.8 


21.6 


10.1 


141 


10.1 


23.4 


10.3 


185 


9.6 


22.2 


9.6 


229 


9.2 


21.0 


10.5 


142 


10.2 


24.4 


9.9 


186 


10.1 


23.5 


10.6 


230 


10.6 


25.1 


10.3 


143 


9.9 


22.3 


9.9 


187 


9.6 


20.0 


8.8 


231 


9.6 


22.6 


10.6 


144 


9.8 


21.5 


10.4 


188 


10.0 


22.0 


9.5 


232 


10.0 


23.0 


10.2 


145 


9.7 


21.8 


9.7 


189 


10.0 


21.9 


9.5 


233 


10.8 


23.4 


10.0 


146 


9.6 


21.4 


10.3 


190 


10.0 


20.3 


10.2 


234 


10.8 


22.5 


9.9 


147 


10.5 


24.3 


10.2 


191 


10.6 


24.0 


9.6 


235 


9.7 


19.3 


9.7 


148 


10.2 


23.5 


10.0 


192 


9.5 


21.6 


9.6 


236 


10.1 


23.0 


10.0 


149 


10.9 


24.3 


9.9 


193 


9.9 


21.7 


10.0 


237 


9.7 


21.3 


10.1 


150 


9.9 


22.7 


10.0 


194 


10.3 


23.9 


10.3 


238 


9.7 


21.1 


9.0 


151 


10.0 


21.8 


9.4 


195 


10.6 


23.5 


9.9 


239 


10.1 


20.7 


10.5 


152 


10.1 


20.4 


10.3 


196 


10.1 


24.2 


10.0 


240 


9.9 


22.0 


9.3 


153 


10.3 


23.4 


9.7 


197 


10.1 


24.0 


10.9 


241 


8.9 


20.0 


10.2 


154 


11.1 


24.0 


10.0 


198 


10.2 


24.1 


10.2 


242 


9.9 


22.8 


10.7 


155 


10.0 


21.1 


9.5 


199 


10.4 


22.4 


9.7 


243 


10.2 


23.3 


9.5 


156 


9.8 


21.0 


10.0 


200 


10.2 


22.5 


10.6 


244 


9.3 


20.3 


9.7 


157 


10.1 


21.7 


10.3 


201 


9.4 


21.1 


10.0 


245 


9.5 


20.8 


9.6 


158 


10.2 


22.0 


10.2 


202 


10.2 


23.0 


10.1 


246 


10.2 


22.4 


10.0 


159 


10.0 


22.4 


9.9 


203 


9.6 


20.3 


9.5 


247 


9.4 


20.0 


9.1 


160 


9.5 


21.2 


10.0 


204 


10.0 


21.9 


9.5 


248 


9.6 


23.3 


10.0 


161 


10.3 


23.0 


10.1 


205 


9.5 


20.8 


9.8 


249 


10.4 


23.8 


10.0 


162 


9.4 


22.0 


9.7 


206 


10.1 


23.5 


10.0 


250 


10.2 


23.9 


10.2 


163 


10.1 


21.0 


9.5 


207 
208 


10.4 
10.0 


24.7 
21.0 


10.4 
9.8 










164 


9.8 


21.9 


10.0 


Average . 


10.05 


22.47 


10.02 


165 


9.7 


22.0 


9.4 


209 


10.1 


23.7 


10.7 


Greatest. 


12.0 


27.9 


11.4 


166 


10.2 


21.5 


9.7 


210 


10.3 


22.8 


10.0 


Least. . . 


8.9 


18.7 


8.8 


167 


10.2 


24.5 


10.5 


211 


10.4 


22.2 


10.1 











In May 1916 Colony E resembled Colony A in development. The 
mollusks were spreading over a wide area and many young and adult 
shells were in evidence everywhere. The same conditions obtained in 
1917, and in January 1919 we were able to state that this colony was 
spreading and multiplying rapidly. Young and old could be seen 
everywhere on the ground. Most of the old were partly burrowed in 
the tilted position, feeding or ovipositing. The extreme young, as 
usual, were mostly about the base of tussocks of grass. Half-grown 
specimens were also plentiful on the moist ground and on the lower 
portion of the bushes and grass. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



23 



Table No. 6. — Measurements of the first generation of Florida-grown Cerion viaregis 
from Loggerhead Key Colony F. 







Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 

whorls. 


of shells. 
















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






vim.. 


mm. 


1 


10.5 


23.3 


11.2 


13 


10.0 


22.5 


11.7 


25 


10.3 


21.5 


12.0 


2 


9.6 


22.0 


10.5 


14 


10.1 


21.6 


11.7 


26 


10.2 


22.3 


12.0 


3 


10.2 


22.6 


12.5 


15 


10.2 


23.5 


12.0 


27 


9.8 


21.1 


11.1 


4 


10.0 


22.6 


11.6 


16 


9.7 


21.4 


11.4 


28 


10.4 


23.0 


11.2 


5 


10.5 


23.5 


12.0 


17 


10.4 


23.5 


11.8 


29 


9.4 


20.7 


12.4 


6 


10.1 


22.0 


11.4 


18 


10.5 


23.5 


12.0 


30 


10.0 


23.2 


12.5 


7 
8 


10.3 
10.5 


22.5 
23.4 


11.8 
11.0 


19 
20 


10.2 
9.7 


22.5 
21.3 


11.5 
12.2 










Average . 


10.15 


22.53 


11.68 


9 


10.3 


22.0 


11.5 


21 


10.6 


24.2 


12.0 


Greatest. 


10.6 


24.2 


12.5 


10 


9.4 


20.0 


11.7 


22 


10.6 


23.3 


11.8 


Least . . . 


9.4 


20.0 


10.5 


11 


10.6 


23.0 


11.6 


23 


10.2 


22.8 


11.3 










12 


9.8 


23.8 


11.0 


24 


10.4 


23.5 


12.0 











Table No. 7. — Measurements of the first generation of Florida-grown Cerion viaregis 
from Loggerhead Key Colony F. 







Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm,. 






mm. 


mm,. 






mm,. 


mm. 


1 


9.8 


20.9 


11.0 


36 


10.1 


20.7 


9.9 


71 


10.6 


23.5 


10.7 


2 


10.0 


19.7 


10.8 


37 


10.5 


23.5 


11.1 


72 


10.3 


22.2 


10.6 


3 


10.0 


22.6 


12.0 


38 


10.0 


22.3 


10.5 


73 


10.5 


22.7 


10.7 


4 


10.0 


22.7 


10.4 


39 


10.0 


22.7 


11.1 


74 


9.9 


20.6 


10.0 


5 


10.1 


22.1 


10.6 


40 


10.5 


23.2 


10.1 


75 


10.3 


22.7 


10.1 


6 


10.4 


23.0 


11.6 


41 


10.0 


21.8 


9.9 


76 


10.0 


21.5 


10.8 


7 


10.5 


22.5 


10.9 


42 


10.3 


22.4 


10.0 


77 


10.6 


24.9 


11.5 


8 


10.2 


22.7 


11.0 


43 


10.4 


21.9 


10.3 


78 


10.2 


23.0 


10.5 


9 


10.4 


21.5 


11.0 


44 


10.4 


23.8 


11.1 


79 


10.3 


23.4 


11.1 


10 


10.2 


22.1 


10.6 


45 


9.6 


21.7 


11.0 


80 


10.5 


23.2 


10.1 


11 


10.4 


21.3 


10.7 


46 


10.3 


22.1 


10.1 


81 


10.4 


23.0 


10.5 


12 


10.3 


22.2 


10.6 


47 


10.2 


24.5 


10.7 


82 


9.6 


21.5 


10.7 


13 


10.1 


22.3 


10.5 


48 


10.9 


24.1 


10.5 


83 


10.1 


21.9 


10.0 


14 


10.3 


24.0 


11.7 


49 


9.7 


20.3 


9.6 


84 


10.1 


22.4 


10.3 


15 


10.1 


21.3 


9.4 


50 


10.2 


22.6 


10.3 


85 


10.2 


22.1 


10.6 


16 


10.2 


23.5 


10.8 


51 


10.0 


21.8 


10.5 


86 


10.0 


21.9 


9.6 


17 


9.5 


19.7 


10.8 


52 


10.0 


22.1 


10.7 


87 


10.3 


27.7 


10.4 


18 


9.8 


21.3 


10.5 


53 


10.6 


23.2 


10.0 


88 


10.3 


22.7 


10.9 


19 


9.6 


22.0 


10.8 


54 


10.6 


24.1 


10.5 


89 


10.1 


22.0 


10.5 


20 


9.6 


21.7 


11.4 


55 


9.8 


21.5 


11.0 


90 


10.4 


23.7 


11.0 


21 


10.2 


21.1 


10.1 


56 


9.9 


22.6 


10.0 


91 


10.1 


23.1 


10.9 


22 


9.7 


20.3 


10.5 


57 


10.6 


24.0 


10.7 


92 


11.0 


24.7 


10.4 


23 


9.8 


21.0 


10.3 


58 


10.1 


22.8 


10.6 


93 


10.6 


24.5 


11.3 


24 


9.7 


21.3 


9.7 


59 


10.3 


22.7 


11.2 


94 


10.0 


22.6 


10.8 


25 


10.3 


24.4 


10.5 


60 


10.5 


22.5 


10.4 


95 


10.2 


23.0 


9.6 


26 


10.3 


23.5 


11.3 


61 


10.2 


21.4 


10.7 


96 


10.4 


22.1 


10.9 


27 


10.4 


21.8 


10.0 


62 


9.8 


21.3 


10.3 


97 


10.7 


25.7 


10.7 


28 


10.3 


22.4 


10.4 


63 


10.4 


23.3 


10.5 


98 


10.6 


21.7 


10.5 


29 


10.5 


24.9 


10.0 


64 


10.0 


21.8 


10.1 


99 


10.5 


23.2 


10.6 


30 


10.2 


21.9 


10.8 


65 


10.0 


23.8 


10.6 


100 


11.0 


23.8 


11.1 


31 
32 


10.3 
11.5 


22.3 
26.8 


10.5 
11.6 


66 
67 


10.6 
10.0 


24.2 
23.1 


10.6 
11.3 










Average . 


10.2 


22.59 


10.6 


33 


9.6 


22.3 


10.6 


68 


9.8 


21.3 


10.3 


Greatest. 


11.5 


27.7 


12.0 


34 


9.6 


23.7 


11.8 


69 


10.5 


23.3 


10.7 


Least . . . 


9.5 


19.7 


9.4 


35 


10.0 


20.6 


10.4 


70 


10.0 


22.5 


10.3 











24 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



The Loggerhead Key Colony F. 

This colony consisted of 500 specimens imported in 1914 from 
Bastian Point, Andros, the same locality from which the original 
specimens of Cerion viaregis were obtained. The colony was placed 
at the south end of Loggerhead Key, S. 24° W., from the long entrance 
stake and S. 80° W. from the double stake which marks Colony E. 
The colony was marked by a stake bearing a tag with the legend 
''Bastian Point, Andros, 1914." 

In June 1915 the colony was thriving, although no young were 
observed, and it was deemed best not to disturb the ground in order to 
see if any were present. 

In May 1916 we gathered 300 tips of the first generation and these 
were planted as Colony M. 

In July 1917 we measured, photographed, and marked 30 adults and 
7 almost full-grown specimens and planted them with Colony M. 
Table 6 gives the measurements. 

In January 1919 we gathered, measured, and photographed 100 
additional first generation Florida-grown specimens of Colony F. 
Table 7 gives the measurements ; the photographs are shown on plates 
22 and 23 and No. 85-100 on plate 24. 

The Loggerhead Key Colony G. 

The original planting of this colony consisted of 300 young specimens 
gathered from Colony E in April 1914, some of which were figured on 
plate 5, upper figure, and the 3 full-grown and 3 nearly full-grown 
individuals on plate 3, top row of the 1915 report. This colony is 
placed in a small meadow a little to the northeast of Colony E. It 



Table No. 8. — Measurements of the first generatior 


. of Florida-grown 


Cerion viaregis 










from Loggerhead Key Colony K. 












Measurements 






Measurements 






Measurements 


Serial 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


No. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


m,m. 






mm. 


mm. 






mm. 


mm. 


1 


10.3 


20.0 


9.8 


19 


10.9 


24.2 


11.0 


37 


9.8 


21.1 


9.6 


2 


10.0 


22.8 


10.9 


20 


10.0 


22.0 


10.0 


38 


9.8 


22.5 


10.8 


3 


10.5 


24.4 


11.2 


21 


10.6 


24.8 


10.2 


39 


10.2 


22.8 


10.0 


4 


10.1 


22.7 


11.1 


22 


10.3 


23.6 


10.0 


40 


9.5 


21.5 


10.4 


5 


9.5 


21.4 


10.4 


23 


9.5 


20.0 


9.8 


41 


10.8 


23.2 


10.2 


6 


10.8 


23.2 


11.7 


24 


10.5 


22.6 


10.7 


42 


9.7 


21.0 


9.5 


7 


9.8 


20.0 


11.0 


25 


10.1 


22.2 


10.7 


43 


9.4 


21.1 


10.6 


8 


10.2 


23.6 


11.3 


26 


10.3 


23.6 


11.0 


44 


11.2 


26.0 


10.7 


9 


10.3 


21.9 


10.8 


27 


10.2 


23.0 


10.8 


45 


10.7 


23.7 


10.3 


10 


10.8 


23.2 


10.0 


28 


9.6 


20.2 


10.3 


46 


10.0 


21.5 


11.4 


11 


10.1 


22.3 


10.0 


29 


9.9 


22.8 


10.1 


47 


10.9 


23.8 


10.1 


12 


9.2 


20.4 


9.6 


30 


10. 2 


22.0 


10.1 


48 


9.9 


22.3 


9.5 


13 


10.9 


24.0 


9.6 


31 


10.2 


21.8 


10.0 


49 


9.9 


21.1 


9.8 


14 
15 


10.2 
10.4 


23.0 
23.5 


10.5 
10.2 


32 
33 


9.2 
10.8 


20.0 
24.8 


9.8 
10.8 










Average . 


10.21 


22.53 


10.37 


16 


10.7 


22.3 


10.1 


34 


10.1 


23.7 


10.2 


Greatest. 


11.2 


26.0 


11.7 


17 


11.2 


25.5 


10.4 


35 


10.3 


22.0 


10.1 


Least . . . 


9.2 


20.0 


9.5 


18 


10.4 


22.9 


10.2 


36 


10.2 


22.0 


10.7 











EXPERIMENTS IN THE BREEDING OF CERIONS. 



25 



is on a ridge in a scanty growth of Uniola paniculata and the place is 
marked by a stake bearing a tag with the legend ^'Cerions, Z." In 
June 1915 we gathered 49 adult or almost adult specimens from this 
colony. These were measured, photographed, and planted in a little 
meadow to the west of Colony F, at a place marked with a stake 
bearing the legend "Cerions, 1915, K." The measurements are shown 
in table 8, while the figures appear on plate 25. 

In May 1916 we gathered 78 additional adult specimens of the first 
generation of Florida-grown individuals in this colony, which were 
photographed and returned to the stake marking this colony. For 
measurements of these see table 9, and for the pictures see plates 26 and 
27 and figures 73-78 of plate 24. 



Table No. 9.— 


Measurements of the first generation 


of Florida-grown 


Cerion viaregis 










from Loggerhead Key Colojiy G. 














Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whorls. 


of shells. 
















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






m,m.. 


mm. 






mm. 


mm.. 


1 


9.7 


21.9 


10.6 


29 


10.3 


23.5 


10.5 


57 


10.5 


24.0 


11.1 


2 


10.3 


24.8 


11.0 


30 


10.6 


23.4 


10.2 


58 


10.2 


22.0 


10.1 


3 


10.4 


23.5 


10.2 


31 


9.9 


24.0 


11.2 


59 


9.8 


21.3 


10.5 


4 


10.6 


23.7 


10.5 


32 


10.0 


22.8 


10.0 


60 


9.7 


22.0 


10.8 


5 


9.7 


21.3 


10.6 


33 


11.1 


25.5 


10.5 


61 


10.0 


22.4 


10.1 


6 


10.2 


24.0 


10.6 


34 


10.7 


24.3 


10.6 


62 


10.8 


24.1 


11.0 


7 


10.6 


23.5 


11.0 


35 


10.4 


24.0 


11.0 


63 


10.6 


24.0 


10.0 


8 


10.0 


20.9 


10.2 


36 


10.3 


23.1 


10.2 


64 


10.3 


24.0 


10.5 


9 


10.0 


24.1 


10.1 


37 


9.7 


23.0 


11.2 


65 


9.9 


22.3 


10.1 


10 


9.6 


21.0 


10.1 


38 


10.1 


23.3 


10.8 


66 


10.2 


23.5 


10.4 


11 


9.8 


22.3 


11.0 


39 


9.3 


22.1 


10.3 


67 


10.4 


23.4 


11.0 


12 


10.2 


22.1 


10.5 


40 


9.8 


22.0 


11.0 


68 


10.1 


26.0 


11.0 


13 


11.2 


26.0 


11.6 


41 


10.0 


22.3 


11.1 


69 


10.2 


23.1 


10.1 


14 


9.7 


21.7 


11.9 


42 


10.5 


24.0 


11.0 


70 


9.7 


22.5 


11.0 


15 


10.1 


23.0 


10.5 


43 


9.9 


22.3 


11.0 


71 


10.5 


24.9 


10.9 


16 


10.3 


23.7 


10.2 


44 


10.1 


23.7 


11.1 


72 


10.8 


24.9 


11.0 


17 


10.7 


25.0 


11.0 


45 


10.8 


24.0 


10.6 


73 


10.4 


24.0 


11.5 


18 


10.7 


24.0 


10.3 


46 


10.2 


24.1 


10.3 


74 


10.6 


24.6 


10.3 


19 


10.6 


25.0 


11.0 


47 


10.1 


22.3 


10.1 


75 


10.2 


22.7 


10.8 


20 


10.1 


25.0 


11.2 


48 


10.1 


24.5 


11.1 


76 


10.3 


23.4 


10.2 


21 


9.7 


23.0 


11.0 


49 


10.0 


22.8 


11.0 


77 


10.1 


23.0 


10.6 


22 


9.5 


21.5 


10.1 


50 


10.5 


23.0 


11.1 


78 


10.6 


25.1 


11.1 


23 


9.9 


23.3 


11.0 


51 


10.0 


22.5 


10. 1 










24 


10.8 


27.0 


11.0 


52 


9^3 


21.7 


10^5 


Average . 


10.2 


23.39 


10.7 


25 


10.1 


24.0 


10.3 


53 


10.2 


23.0 


10.4 


Greatest. 


11.2 


27.0 


11.9 


26 


10.3 


23.8 


11.1 


54 


10.1 


23.2 


10.6 


Least. . . 


9.3 


20.9 


10.0 


27 


10.1 


23.1 


11.1 


55 


10.2 


23.0 


10.4 










28 


10.0 


23.2 


11.7 


56 


10.3 


24.6 


11.1 











In January 1919 we found many shells of various ages scattered over 
the ground, and the colony, although small, is doing well. 

The Loggerhead Key Colont H. 

On June 8, 1912, a planting of 500 each of Cerion viaregis and Cerion 
casahlancce was made on the south side of the path leading from the 
light-house to the boat-house on the west shore, in order to determine 
if these two forms would cross when given an opportunity. 



26 EXPERIMENTS IN THE BREEDING OF CERIONS. 

In May 1913 we observed that several dead Cerion shells, evidently 
belonging to this colony, were occupied by small hermit crabs in the 
neighborhood. 

In April 1914 we found that part of the ground occupied by this 
colony had been burned over and quite a number of the shells destroyed. 
Most of the living shells were in the fringe of live bay cedars. As we 
did not deem this habitat quite suitable, we cleared the place thor- 
oughly by pulling the cactus and cutting the grass. This exhaustive 
search resulted in the recovery of 200 Cerion casahlancce and 150 Cerion 
viaregis and a single young tip. We planted all this material in a new 
location, which will be referred to in the future as Colony I. 

In June 1915 quite a number of specimens were discovered in the 
fringe of bay cedars bordering the west side of the original planting 
which we overlooked in 1914. We left these undisturbed. 

In May 1916 we found that this colony had again been subjected to a 
severe burning and it was doubted if anything had survived. 

No specimens were seen in 1917. 

In January 1919 this place was so heavily overgrown with Uniola 
paniculata that it was impossible to see anything of Cerions that 
might have escaped our collecting and the fire. 

The Loggerhead Key Colony I. 

This colony (consisting of 200 Cerion viaregis, 150 Cerion casahlancce, 
and a single tip which were transferred from Colony H in April 1914) 
is located in the second meadow northwest of Colony E, in a coarse 
calcareous sand plain having a good stand of Sporoholus virginicus, 
the whole being fringed by bay cedars. 

The colony was doing well in June 1915, but in May 1916 we found 
55 of the planted moUusks dead; of these 28 belonged to Cerion via- 
regis and 27 to Cerion casahlancce; 18 young individuals of various 
sizes were also observed. 

In July 1917 we discovered some adult first generation Florida- 
grown Cerions in this colony, but all were readily referable to either 
Cerion casahlancce or Cerion viaregis. Apparently no crossing had 
taken place. 

In January 1919 we gathered up all the material discoverable in this 
planting and secured 58 marked and 43 unmarked specimens of Cerion 
viaregis and 54 marked and 105 unmarked Cerion casahlancce. All the 
unmarked specimens, which represent the first generation of Florida- 
grown material, were at once referable to one or the other of the two 
species; no intermediates of any kind appeared. It seems reasonable, 
therefore, to beUeve that these two species do not cross. This is not 
at all surprising when one considers the differences in the anatomical 
structures, as pointed out in the anatomical discussion of the various 
forms transplanted. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



27 



The Loggerhead Key Colony K. 

In June 1915 we gathered 646 specimens of the first generation of 
Florida-grown individuals at Colony E, of which 250 were photo- 
graphed and measured and reported under that colony. The entire 
lot was then planted in a httle meadow to the west of Colony E, which 
is separated from Colony K by a fringe of bay cedars. They are in the 
north end of this meadow, the ground being covered by a mixed 
growth of Uniola paniculata and Sporoholus virginicus. The planting 
is marked by a stake bearing a tag with the legend "Cerions, 1915, K." 

Table No. 10. —Measurements of the second generation of Florida-grown Cerion viaregis 
from Loggerhead Key Colony K. 







Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 

whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






nun. 


mm. 






mm,. 


mm. 






vim. 


mm. 


1 


9.5 


22.5 


10.8 


36 


10.0 


22.3 


11.1 


71 


10.1 


22.0 


10.8 


2 


10.0 


23.0 


10.0 


37 


9.9 


20.7 


11.3 


72 


10.2 


22.2 


10.8 


3 


10.4 


23.5 


10.1 


38 


10.6 


22.9 


10.1 


73 


10.0 


22.4 


11.8 


4 


10.0 


21.4 


10.8 


39 


10.1 


21.9 


10.5 


74 


9.6 


22.8 


11.4 


5 


10.5 


24.8 


10.7 


40 


10.5 


23.0 


11.2 


75 


10.3 


22.2 


10.0 


6 


10.4 


24.1 


11.0 


41 


10.5 


24.0 


11.3 


76 


11.0 


22.7 




7 


10.0 


22.3 


10.7 


42 


10.6 


23.0 


10.0 


77 


10.0 


21.5 


ii!o 


8 


10.0 


23.7 


11.1 


43 


10.0 


22.1 


10.6 


78 


10.1 


22.0 


12.0 


9 


10.5 


24.4 


11.3 


44 


10.2 


22.6 


10.7 


79 


10.5 


24.2 


11.0 


10 


10.3 


23.0 


10.6 


45 


10.6 


25.4 


10.2 


80 


10.0 


22.3 


10.4 


11 


10.2 


24.5 


11.7 


46 


10.1 


22.4 


11.2 


81 


10.1 


23.1 


10.2 


12 


10.0 


22.2 


10.3 


47 


10.5 


23.3 


10.6 


82 


9.9 


21.3 


10.3 


13 


10.2 


22.6 


11.0 


48 


10.5 


23.8 


9.6 


83 


10.0 


23.0 


11.0 


14 


10.9 


25.0 


11.4 


49 


10.2 


22.1 


10.3 


84 


10.2 


23.2 


10.2 


15 


10.3 


23.4 


10.5 


50 


11.3 


26.0 


11.9 


85 


8.4 


17.3 


11.0 


16 


10.2 


23.0 


10.5 


51 


9.6 


22.5 


10.8 


86 


10.0 


21.3 


10.8 


17 


10.0 


24.6 


10.6 


52 


10.1 


24.7 


11.0 


87 


10.2 


23.2 


11.1 


18 


10.2 


23.4 


11.1 


53 


10.0 


22.2 


11.0 


88 


10.2 


21.9 


10.6 


19 


10.0 


21.5 


11.0 


54 


9.5 


22.0 


10.9 


89 


10.5 


24.8 


10.9 


20 


10.2 


22.5 


11.6 


55 


10.3 


23.8 


12.3 


90 


10.1 


22.0 


10.9 


21 


9.6 


21.9 


11.3 


56 


9.8 


21.0 


11.4 


91 


10.3 


23.0 


11.4 


22 


10.6 


23.1 


11.7 


57 


10.4 


23.0 


10.0 


92 


10.1 


22.6 


10.4 


23 


10.5 


23.8 


10.6 


58 


10.0 


22.2 


11.0 


93 


11.1 


23.8 


10.2 


24 


10.6 


23.7 


11.4 


59 


10.9 


23.4 


10.7 


94 


10.1 


24.4 


9.7 


25 


10.3 


22.2 


10.7 


60 


10.2 


22.2 


10.5 


95 


10.8 


23.5 


10.7 


26 


10.2 


22.7 


11.0 


61 


9.9 


20.6 


10.6 


96 


10.5 


23.1 


10.0 


27 


10.0 


24.0 


10.4 


62 


10.3 


23.8 


11.1 


97 


10.5 


24.0 


10.2 


28 


10.0 


22.3 


11.3 


63 


10.5 


26.8 


11.0 


98 


10.6 


24.0 


11.6 


29 


10.1 


21.6 


10.7 


64 


9.6 


19.9 


10.2 


99 


10.0 


22.0 


9.9 


30 


10.9 


23.6 


11.7 


65 


11.2 


24.8 


11.0 


100 


10.2 


22.1 




31 

32 


10.0 
10.2 


22.0 
24.5 


11.0 
10.9 


66 
67 


11.0 

9.8 


25.0 
21.2 


11.0 
11.2 










Average . 


10.22 


22.86 


10.84 


33 


10.1 


22.0 


10.7 


68 


9.8 


21.9 


11.0 


Greatest. 


11.3 


26.8 


12.3 


34 


10.3 


23.2 


11.6 


69 


10.2 


21.4 


10.1 


Least . . . 


8.4 


17.3 


9.6 


35 


11.1 


23.8 


11.5 


70 


9.8 


21.2 


10.1 











This colony was thriving in May 1916. 

In July 1917 we found 2 adults of the second generation as well as a 
large number of young individuals. 

In January 1919 this colony was again examined and 100 adult 
specimens of the second generation were secured, measurements of which 
are given in table 10 and photographs of them on plates 28 and 29. 



28 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



The Loggerhead Key Colony M. 

In May 1916 we planted 300 tips taken from Colony F, representing 
the first generation of Florida-grown Cerion viaregis of the 1914 
planting. This colony was placed a little south of the entrance stake to 
Colony E, on the inner edge of the outer sand dune, which is covered 
by a mixed growth of Uniola paniculata and Sporoholus virginicus with 
a few bay cedars and small specimens of Tournefortia. The place is 
marked by a stake and a tag bearing the legend ''Cerions, 1916, M." 

In July 1917 we gathered, measured, and photographed 26 full-grown 
individuals of this colony (table 11) ; 30 adult and 7 almost adult from 
Colony F were added to the colony on this date. 





Table No. 11.- 


—Measurements of the first generation of Florida-grown Cerion viaregis 










Loggerhead Key Colony M. 














Measurements 






Measurements 






Measurements 


Serial 


No. of 


of shells. 


Serial 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


No. 


whorls. 




No. 












.^t. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






m,m,. 


mm. 


1 


10.2 


23.0 


12.0 


11 


9.7 


21.2 


10.9 


21 


10.1 


23.1 


13.0 


2 


10.2 


22.0 


11.5 


12 


10.8 


23.8 


12.0 


22 


9.7 


21.2 


12.0 


3 


10.5 


24.0 


11.4 


13 


10.9 


24.5 


11.0 


23 


10.2 


22.3 


11.4 


4 


10.4 


23.2 


11.4 


14 


10.1 


22.7 


11.7 


24 


9.4 


20.0 


11.2 


5 


10.0 


23.8 


12.1 


15 


10.2 


22.0 


12.0 


25 


9.6 


21.0 


11.3 


6 


10.1 


22.4 


11.5 


16 


10.2 


24.5 


13.0 


26 


9.8 


21.2 


11.0 


7 


9.5 


20.1 


11.8 


17 


10.2 


24.1 


11.5 
















8 


10.2 


23.6 


12.4 


18 


10.5 


21.7 


12.0 


Average . 


10.14 


22.63 


11.71 


9 


10.0 


22.7 


11.9 


19 


10.2 


23.5 


11.6 


Greatest. 


10.9 


24.5 


13.0 


10 


10.8 


24.1 


11.4 


20 


10.2 


22.8 


11.5 


Least . . . 


9.4 


20.0 


10.9 



In June 1919 we collected 100 adults and 35 tips of the second genera- 
tion of Cerion viaregis. The adults were photographed and measured. 
The photographs are shown on plates 30 and 31, while the measurements 
are given in table 12. The whole lot was planted as Colony P. 

The Loggerhead Key Colony P. 

This colony, when planted in January 1919, consisted of 100 adult 
and 35 tips of the second generation Florida-grown Cerion viaregis 
taken from Colony K. It is about 60 feet northwest of the entrance 
stake to Colony E on the east side, a little west of the line between the 
entrance stake and the light-house. The coarse calcareous sandy 
ground is covered by a scattered growth of Sporoholus virginicus and 
Uniola paniculata and fringed with bay cedars. The place is marked 
by a short stake bearing a tag with the legend "Cerions, 1919, P." 

The Loggerhead Ivey Colony Q. 

Colony Q consists of 100 adult and 5 tips of Cerion viaregis from 
Colony M, second generation Florida-grown individuals. It is on the 
outer dune on the east side, about 200 feet north of the entrance stake 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



29 



to Colony E. The ground here is covered by a scattered growth of 
Uniola paniculata and Sporobolus virginicus. The place is marked by a 
short stake bearing a tag with the legend "Cerions, 1919, Q." 

Table No. 12. — Measurements of the second generation of Florida-grown Cerion viaregis 
from Loggerhead Key Colony M. 







Measurements 






Measurements 






Measurements 


Serial 


No. of 


of shells. 


Serial 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


No. 


whorls. 


1 


No. 














Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


11.1 


25.5 


10.8 


36 


10.3 


23.3 


10.3 


71 


10.6 


25.2 


11.4 


2 


10.2 


22.0 


10.6 


37 


11.3 


25.4 


12.3 


72 


10.0 


24.3 


11.6 


3 


10.0 


22.3 


10.4 


38 


10.2 


23.8 


11.1 


73 


11.1 


22.7 


10.8 


4 


10.2 


22.0 


10.0 


39 


10.4 


22.8 


11.3 


74 


10.4 


23.5 


10.7 


5 


11.3 


24.5 


9.8 


40 


10.3 


25.0 


11.0 


75 


10.5 


25.9 


10.6 


6 


10.5 


24.7 


11.2 


41 


10.4 


23.0 


10.3 


76 


10.4 


24.8 


12.0 


7 


9.4 


20.7 


10.2 


42 


10.7 


24.2 


11.0 


77 


10.0 


21.3 


10.8 


8 


10.0 


21.8 


9.3 


43 


10.5 


22.7 


10.2 


78 


10.6 


22.5 


10.3 


9 


10.5 


23.7 


9.7 


44 


10.3 


22.5 


10.6 


79 


9.6 


21.3 


9.8 


10 


10.2 


21.8 


10.3 


45 


10.9 


24.9 


12.2 


80 


10.1 


21.4 


12.0 


11 


10.9 


24.6 


10.2 


46 


9.8 


20.5 


10.3 


81 


10.1 


25.1 


11.5 


12 


10.5 


23.9 


10.4 


47 


10.8 


23.8 


10.7 


82 


10.0 


23.9 


11.8 


13 


10.2 


23.6 


11.0 


48 


10.8 


23.3 


12.1 


83 


9.9 


21.2 


10.3 


14 


10.1 


21.8 


10.3 


49 


9.7 


20.9 


9.6 


84 


9.2 


19.4 


9.7 


15 


10.3 


22.7 


9.8 


50 


10.2 


23.0 


10.6 


85 


10.6 


24.5 


10.6 


16 


10.2 


24.2 


10.7 


51 


10.3 


23.8 


10.7 


86 


9.3 


21.8 


10.2 


17 


10.0 


20.8 


10.3 


52 


10.6 


22.2 


10.4 


87 


10.6 


24.7 


10.5 


18 


10.4 


23.7 


10.5 


53 


10.2 


23.2 


10.0 


88 


10.1 


21.8 


12.0 


19 


10.3 


22.1 


10.0 


54 


10.6 


24.8 


11.8 


89 


9.7 


21.1 


10.0 


20 


10.1 


23.0 


9.9 


55 


10.0 


23.7 


11.1 


90 


9.9 


19.9 


10.6 


21 


10.7 


24.3 


10.0 


56 


11.0 


26.0 


11.8 


91 


10.5 


24.0 


10.5 


22 


9.8 


22.6 


11.1 


57 


10.5 


25.3 


10.3 


92 


10.3 


22.5 


11.2 


23 


10.3 


23.9 


11.1 


58 


10.3 


24.0 


11.9 


93 


11.0 


26.3 


11.0 


24 


10.5 


25.1 


11.1 


59 


11.2 


24.9 


10.7 


94 


10.3 


23.0 


10.8 


25 


10.6 


23.5 


10.3 


60 


10.3 


22.1 


10.6 


95 


10.1 


22.3 


11.0 


26 


10.4 


23.0 


10.4 


61 


10.8 


25.5 


10.3 


96 


10.2 


23.0 


10.2 


27 


10.5 


23.4 


10.4 


62 


10.7 


24.6 


11.5 


97 


10.1 


23.7 


10.8 


28 


11.3 


28.1 


12.1 


63 


10.1 


22.9 


9.8 


98 


10.1 


23.0 


11.2 


29 


10.3 


22.1 


10.4 


64 


10.6 


22.9 


10.9 


99 


10.3 


23.6 


11.4 


30 
31 


10.1 
10.3 


23.0 
22.5 


11.0 
10.6 


65 
66 


11.1 
10.4 


27.3 
24.2 


11.6 
11.2 


100 


9.3 


21.0 


9.9 










32 


10.2 


20.2 


10.2 


67 


10.6 


24.4 


11.8 


Average . 


10.33 


23.24 


10.73 


33 


10.1 


23.1 


11.0 


68 


11.0 


25.2 


10.5 


Greatest. 


11.3 


28.1 


12.3 


34 


10.1 


20.2 


10.2 


69 


10.3 


23.3 


10.8 


Least . . . 


9.2 


19.4 


9.3 


35 


10.0 


21.2 


10.5 


70 


9.9 


21.0 


10.7 











The Loggerhead Key Colony R. 



This consists of 200 of the first generation of Florida-grown Cerion 
viaregis from Colony F, and is planted 140 feet west of Colony M, in a 
small meadow supporting a scattered growth of Uniola paniculata and 
Sporobolus virginicus. The place is marked by a short stake bearing 
a tag with the legend "Cerions, 1919, R." 



30 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



DISCUSSION OF DATA. 

First Generation of Florida-grown Cerion viaregis. 

In reviewing the pictures of all the first-generation specimens of 
Florida-grown Cerion viaregis and comparing them with the check 
series of specimens found on Andros Island, Bahamas, one is led to the 
conclusion that, as far as general shape and sculpture are concerned, 
little or no new variations have appeared in the Florida-grown speci- 
mens. Whatever variation occurs in the Florida specimens is also to 
be found in the check series from Andros Island. An analysis of the 
measurements of the first generation of all the Florida-grown specimens 
gives the results shown in table 13. 

Table No. 13. — First generation Florida-grown Cerion viaregis. 



Colony. 



No. of 
whorls. 



Altitude. 



Greater 
diameter. 



No. of 
specimens. 



Averages: 

Second Key north of Sands Key 

Boca Grande Key 

Loggerhead Key, Colony E 

Loggerhead Key, Colony F, 1917 

Loggerhead Key, Colony F, 1919 

Loggerhead Key, Colony G, 1915 

Loggerhead Key, Colony G, 1916 

Loggerhead Key, Colony M 

Average of all Florida-grown first 

generation 

Average of check series 

Greatest: 

Second Key north of Sands Key 

Boca Grande Key 

Loggerhead Key, Colony E 

Loggerhead Key, Colony F, 1917 

Loggerhead Key, Colony F, 1919 

Loggerhead Key, Colony G, 1915 

Loggerhead Key, Colony G, 1916 

Loggerhead Key, Colony M 

Greatest of all Florida-grown first 

generation 

Greatest of check series 

Least: 

Second Key north of Sands Key 

Boca Grande Key 

Loggerhead Key, Colony E 

Loggerhead Key, Colony F, 1917 

Loggerhead Key, Colony F, 1919 

Loggerhead Key, Colony G, 1915 

Loggerhead Key, Colony G, 1916 

Loggerhead Key, Colony M 

Least of all Florida-grown first 

generation 

Least of check series 



10.03 
10.31 
10.05 
10.15 
10.20 
10.21 
10.20 
10.14 



mm. 

22.82 

23.57 

22.47 

22.53 

22.59 

22.73 

23.39 

22.63 



mm. 

10.40 

10.46 

10.02 

11.68 

10.60 

10.37 

10.70 

11.71 



76 

107 

250 

30 

100 

49 

78 

26 



10.16 
10.08 



22.84 
22.56 



10.74 
11.13 



716 



11.0 
11.2 
12.0 
10.6 
11.5 
11.2 
11.2 
10.9 



25.8 
27.1 
27.9 
24.2 
27.7 
26.0 
27.0 
24.5 



11.4 
11.6 
11.4 
12.5 
12.0 
11.7 
11.9 
13.0 



12.0 
11.0 



27.9 
27.0 



13.0 

12.7 



8.9 
9.5 
8.9 
9.4 
9.5 
9.2 
9.3 
9.4 



19.2 
20.2 
18.7 
20.0 
19.7 
20.0 
20.9 
20.0 



9.5 

9.0 

8.8 

10.5 

9.4 

9.5 

10.0 

10.9 



8.9 
9.1 



18.7 
19.0 



9.0 



EXPERIMENTS IN THE BREEDING OF CERIONS. 31 

Table 13 indicates merely that we have in this Florida-grown mate- 
rial a very slightly larger range of variation, but no difference in type. 
The largest number of whorls observed in any member of this genera- 
tion is 12 mm. and the least 8.9 mm. In the check series we find 11 
mm. and 9.1 mm. The largest altitude observed in this generation was 
27.9 mm. and the smallest 18.7 mm., while in the check series the 
largest was 27 mm. and the smallest 19 mm. The greater diameter 
of our Florida-grown material was 13 mm. and the least 8.8 mm., 
whereas in the check series we obtained 12.7 mm. for the largest 
measurement and 9 mm. for the least. A comparison of the average 
measurements of all the Florida-grown first generation material with 
the average measurement of the check series presents the following: 

Number of whorls, 10.16 for the Florida-grown specimens and 10.08 for the check series. 
Altitude, 22.84 mm. for the Florida-grown generation and 22.56 for the check series. 
Greatest diameter, 10.74 mm. for the Florida-grown specimens against 11.13 mm. for the 
check series. 

The trifling discrepancies in measurements, therefore, as well as 
sculpture, enable us to say that the amount of increased variation 
noted in the Florida-grown material is practically nil. It is not at all 
unreasonable to believe that if an equally large number of Bahama 
shells had been subjected to analysis parallel results might have been 
obtained. 

Second Generation of Florida-grown Cerion viaregis. 

Of the second generation of Florida-grown Cerion viaregis, we have 
now had 208 specimens from three different colonies. Table 14 gives 
the measurable data presented by these and makes a comparison with 
the check series from Andros Island, Bahamas. 

This discloses that the second generation of Florida-grown material 
of Cerion viaregis is also slightly more variable than the check series 
of Bahama material, for here we find that the greatest number of 
whorls is 11.3 mm., while in the check series it is 11 mm. The altitude 
measurement is 28.1 mm. against 27 mm. of the check series, while 
the average greater diameter is a little less than that of the check 
series, namely, 12.3 mm. against 12.7 mm. The least number of 
whorls observed in any of the members of the second generation of 
Florida-grown Cerion viaregis is 8.4 nam., while in the check series the 
least observed was 9.1 mm. The least altitude of the Florida-grown 
specimens is 17.3 mm. against 19 mm. of the check series, and the 
least diameter is 9.3 mm. against 9 mm. of the check series. 

Table 15 shows that in the number of whorls the second Florida- 
growTi generation presents only a negligible increase over the Bahaman 
check series and the first Florida generation ; it likewise shows an aver- 
age altitude measurement a little higher than the other two, but an 
average diameter measurement halfway between the check series and 



32 EXPERIMENTS IN THE BREEDING OF CERIONS. 

Table No. 14. — Second generation of Florida-grown Cerion viaregis. 



Colony. 


No. of 
whorls. 


Altitude. 


Greater 
diameter. 


No. of 
specimens. 


Averages: 

Second Key north of Sands Key 

Loggerhead Key, Colony K 


10.21 
10.22 
10.33 


mm. 
22.95 
22.86 
23.24 


mm. 
10.87 
10.84 
10.73 


8 
100 
100 


Loggerhead Key, Colony M 


Average of all Florida-grown second 
generation 


10.25 
10.08 


23.01 
22.56 


10.81 
11.13 


208 


Average of check series 


Greatest: 

Second Key north of Sands Key 

Loggerhead Key, Colony K 


11.1 
11.3 
11.3 


24.2 
26.8 
28.1 


11.3 
12.3 
12.3 




Loggerhead Key, Colony M 


Greatest of all Florida-grown second 
generation 


11.3 
11.0 


28.1 
27.0 


12.3 
12.7 


Greatest of check series 


Least: 

Second Key north of Sands Key 

Loggerhead Key, Colony K 


9.6 
8.4 
9.2 


21.0 
17.3 
19.4 


10.2 
9.6 
9.3 


Loggerhead Key, Colony M 


Least of all Florida-grown second 
generation 


8.4 
9.1 


17.3 
19.0 


9.3 
9.0 


Least of check series 





Table No. 15. — Comparison between check series of Cerion viaregis and first and second 
generation of Florida-grown specimens. 





No. of 
whorls. 


Altitude. 


Greater 
diameter. 


Averages: 

Check series 


10.08 
10.16 
10.25 


mm. 
22.56 
22.84 
23.01 


mm. 
11.13 
10.74 
10.81 


First generation Florida-grown specimens 

Second generation Florida-grown specimens 


Greatest: 

Check series 


11.0 
12.0 
11.3 


27.0 
27.9 
28.1 


12.7 
13.0 
12.3 


First generation Florida-grown specimens 


Second generation Florida-grown specimens 


Least: 

Check series 


9.1 
8.9 

8.4 


19.0 

18.7 
17.3 


9.0 

8.8 
9.3 


First generation Florida-grown specimens 


Second generation Florida-grown specimens 





the first generation. The specimen having the greatest number of 
whorls in the second generation has less than the specimen having the 
greatest number of whorls in the first generation. In that respect it is 
nearer to the specimen having the greatest number of whorls in the 
check series, but the amount of variation there may again be said to 
be negligible. In altitude we find one specimen in the second genera- 



EXPERIMENTS IN THE BREEDING OF CERIONS. 33 

tion which exceeds by 1.2 mm. any found in the check series or in the 
first generation. Cerions are fairly variable in measurements, as 
shown in our series, and this one large exceptional specimen does not 
really mean anything in this instance. 

The greatest diameter presented by any specimen of the second 
generation is a little less than that presented by any member of the 
check series or the first generation. When it comes to the least meas- 
urement we find that in the number of whorls the second generation 
has given us a specimen with 8.4 whorls, which is less than that pre- 
sented by any form of the check series or the first generation. In the 
altitude measurements, too, we find one specimen with 17.3 mm., 
which is considerably less than the altitude of the two other groups, 
while in the measurement of the diameter the least diameter shown by 
any specimen of the second generation is slightly greater than that of 
the check series or the members of the first generation. However, 
it is perfectly safe to say that all the variations presented by the 
Florida-grown first and second generation specimens do not speak 
for any material change having taken place within this group. I feel 
perfectly confident that all the variations presented here are entirely 
within the range of Cerion viaregis as it occurs at Bastian Point. This, 
then, means that the changed environment to which we have subjected 
these organisms in transplanting them to Florida has not affected 
them in such a way as to produce such differences as one observes 
between the various colonies in the Bahamas. That is, that Cerion 
viaregis seems to be quite stable within its normal limits of variation 
and appears to adhere to these limits even when subjected to a decidedly 
changed environment. 

Cerion casablanc^ Bartsch. 

Of this species 100 specimens have been taken at random from a lot 
collected in the White House region on Andros. Figures of these are 
given upon plates 32-34. Their measurements are shown in table 16. 
These specimens are entered as Cat. No. 334723, U. S. N. M., and No. 
13 is selected to serve as type. 

The Colony on the First Ragged Key North of Sands Key. 

On this key 500 specimens of Cerion casablancce were planted in June 
1912, on a sandy ridge on the middle of the outside of the key. Here 
we have a fringing element of bay cedar to the seaward, as well as on the 
inner margin of the dune. The dune itself contains a sparse growth of 
Sporoholus virginicus, some Hymenocallis, and a very dense matting of 
Sesuvium portulacastrum. 

On April 25, 1913, we found most of the planted specimens attached 
to the stems and leaves of the succulent Sesuvium; they seemed to be 
thriving in this new habitat. We also discovered 3 young shells having 
1.3, 1.5 and 2 postnuclear whorls respectively. 



34 



EXPERIMENTS IN THE BREEDING OF CERIONS. 









Table No. 16. — Check series of Cerion casablancoe. 












Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 


No. of 
whoris. 


of shells. 










No. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm,. 


1 


10.6 


24.1 


12.0 


36 


10.1 


24.9 


13.8 


71 


11.0 


27.1 


13.5 


2 


10.4 


26.9 


12.9 


37 


12.1 


32.9 


13.8 


72 


10.4 


26.2 


12.6 


3 


11.0 


26.7 


11.3 


38 


10.4 


26.2 


13.2 


73 


11.0 


25.8 


14.6 


4 


11.3 


28.3 


12.8 


39 


11.0 


28.3 


14.5 


74 


11.1 


26.9 


12.7 


5 


10.4 


24.0 


11.0 


40 


10.8 


26.6 


14.8 


75 


10.6 


27.6 


13.6 


6 


10.9 


26.0 


12.6 


41 


11.5 


29.0 


14.3 


76 


10.9 


26.2 


14.1 


7 


10.9 


26.9 


12.5 


42 


10.1 


25.2 


13.6 


77 


10.9 


25.3 


14.0 


8 


10.0 


25.0 


11.8 


43 


11.9 


30.0 


13.2 


78 


11.3 


28.0 


14.0 


9 


10.6 


25.5 


11.5 


44 


11.2 


27.0 


13.9 


79 


11.1 


27.5 


14.3 


10 


10.4 


26.8 


12.6 


45 


10.8 


26.5 


11.8 


80 


10.5 


24.6 


13.9 


11 


10.9 


25.3 


12.8 


46 


10.1 


24.9 


12.9 


81 


10.9 


25.5 


15.0 


12 


11.2 


29.2 


13.4 


47 


10.9 


27.2 


14.3 


82 


11.1 


27.3 


13.1 


13 


10.7 


27.6 


13.7 


48 


10.9 


26.4 


13.5 


83 


10.6 


26.3 


14.2 


14 


10.6 


26.0 


13.2 


49 


11.1 


29.4 


13.6 


84 


11.0 


26.1 


12.7 


15 


11.0 


27.3 


14.4 


50 


11.1 


27.1 


14.4 


85 


10.9 


25.1 


14.1 


16 


11.1 


29.4 


14.5 


51 


10.7 


26.5 


14.0 


86 


10.1 


26.0 


13.2 


17 


11.6 


30.3 


13.8 


52 


10.5 


25.1 


13.5 


87 


10.5 


25.8 


15.1 


18 


11.2 


31.4 


14.8 


53 


10.7 


28.5 


14.6 


88 


10.5 


26.8 


14.5 


19 


10.8 


28.0 


13.2 


54 


10.2 


24.2 


13.2 


89 


11.1 


27.0 


14.4 


20 


12.1 


31.6 


13.5 


55 


10.8 


27.3 


13.4 


90 


11.4 


26.0 


13.7 


21 


12.0 


31.5 


15.0 


56 


10.6 


28.2 


15.1 


91 


10.6 


25.3 


13.5 


22 


10.9 


26.7 


13.2 


57 


10.6 


26.0 


15.6 


92 


10.8 


26.5 


13.5 


23 


11.5 


27.7 


14.2 


58 


10.6 


25.2 


13.1 


93 


10.8 


24.8 


14.0 


24 


11.1 


25.8 


15.2 


59 


11.4 


28.2 


14.0 


94 


10.4 


25.7 


14.4 


25 


11.5 


29.2 


13.5 


60 


10.5 


25.8 


13.7 


95 


10.4 


24.7 


13.7 


26 


11.5 


29.2 


14.5 


61 


11.2 


28.5 


14.0 


96 


11.4 


30.0 


14.0 


27 


11.2 


29.0 


14.0 


62 


10.7 


28.3 


14.3 


97 


10.9 


25.4 


15.0 


28 


10.9 


27.7 


13.1 


63 


11.9 


26.6 


14.5 


98 


11.5 


31.6 


14.5 


29 


11.8 


30.9 


14.3 


64 


10.5 


26.7 


13.6 


99 


11.0 


27.9 


15.0 


30 


11.4 


28.9 


13.0 


65 


10.6 


26.3 


15.5 


100 


10.8 


28.6 


15.3 


31 
32 


11.3 
11.1 


29.5 
27.6 


14.3 
13.2 


66 
67 


11.5 
10.5 


29.4 
26.0 


13.2 
14.2 










Average . 


10.92 


27.19 


13.7 


33 


11.0 


29.8 


14.4 


68 


10.8 


26.3 


13.9 


Greatest. 


12.1 


32.9 


15.6 


34 


11.1 


28.7 


12.8 


69 


10.7 


26.4 


14.2 


Least . . . 


10.0 


24.0 


11.0 


35 


10.2 


25.2 


14.0 


70 


11.4 


27.0 


11.9 











In 1914 a house was built in the midst of our plantation, but this has 
not materially affected this planting; 50 young secured in April 1914 
were taken to Sands Key to start a new colony. 

In June 1915 we secured 23 adult specimens of the first generation of 
Florida-grown shells, which we measured and photographed, together 
with 45 young, varying from a quarter-grown to almost adult, on the 
same sand ridge upon which the original planting was made, but about 
50 feet to the north of it. Later we discovered 13 additional adults of 
the first generation, which we Ukewise marked and added to this 
planting. The 23 specimens photographed are represented on plate 
35 and their measurements are given in table 17. 

In 1919 we found that the key had been transferred to a new pur- 
chaser, who was cutting off the bushes. Most of the ground containing 
our second plantation had been completely burned over and we were 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



35 



Table No. 17. — Measurements of the first generation of Florida-grown Cerion casahlancoe 
from the first Ragged Key north of Sands Key. 



Serial 
No. 


No. of 

whorls. 


Measurements 
of shells. 


Serial 
No. 


No. of 
whorls. 


Measurements 
of shells. 


Serial 
No. 


No. of 
whorls. 


Measurements 
of shells. 


Alt. 


Diam. 


Alt. 


Diam. 


Alt. 


Diam. 


1 
2 
3 
4 
5 
6 
7 
8 
9 


10.0 
10.0 
11.0 
10.0 
10.8 
10.5 
10.1 
11.1 
10.9 


mm. 
26.7 
24.7 
25.2 
24.0 
27.4 
30.3 
31.0 
31.3 
32.0 


m.m. 
13.8 
12.5 
14.0 
13.5 
12.6 
14.0 
13.9 
14.0 
14.0 


10 
11 
12 
13 
14 
15 
16 
17 
18 


10.7 
10.5 
10.9 
10.8 
10.3 
10.8 
10.7 
10.0 
10.2 


mm. 
29.6 
29.5 
29.3 
30.1 
28.9 
29.3 
29.0 
28.9 
28.1 


mm. 

14.0 

13.8 

13.3 

14.0 

13.9 

14.0 

14.2 

15.0 

14.2 


19 
20 
21 
22 
23 

Average . 
Greatest. 
Least. . . 


10.1 
10.5 
10.1 
10.3 
10.0 


m.m. 
28.0 
26.9 
27.0 
27.6 
26.2 


mm. 
13.0 
13.3 
12.9 
13.3 
12.5 


10.45 

11.1 

10.0 


28.31 

32.0 

24.0 


14.1 
15.0 
12.5 



able to find only 2 of the marked shells and 2 which belong to the second 
generation. These are numbers 24 and 25 of plate 35. The original 
planting about the house escaped the burning, but we fear that the new 
buildings which are to be erected, as well as the human activities which 
are to be displayed upon this key, will probably table No 18 

exterminate this planting. The measurements 
of two specimens of the second Florida-grown 
generation are given in table 18. 



No. of 
whorls. 


Alt. 


Diam. 


11 
10.2 


mm. 

31.3 

26.6 


mm. 
14.4 
15.0 



The Colony on Sands Key. 

In April 1914 we planted 50 tips, varying in 
size from nepionic shells to half-grown indi- 
viduals. These were placed in the middle of 
the first sand stretch south of the north end on the seaward side. 
The place is marked by a skinned, bleached, white tree, which forms a 
conspicuous landmark on the sea-side. There were two lesser dead 
trees on each side of the taller stump. The specimens were placed in a 
patch of grass near the base of the outer dead tree, which appeared to be 
a very favorable habitat. 

In June 1915 we found only a single half-grown specimen, and since 

then not one has been discovered. Previous experience, however, 

would lead us to believe that it is possible that members of this little 

colony may still survive and in course of time may populate the 

region. 

The Colony on Indian Kjey. 

On June 1, 1912, we placed 500 specimens of Cerion casablancce about 
the ruins of an old house on the bay side of the key. When we visited 
this planting on April 26, 1913, the Cerions were doing well, some of 
them having moved fully 60 feet from the place where they had been 
dropped. Most of those seen were on dead sticks, usually clustered in 
groups, though many were on the rank growth of Sesuvium portulacas- 
trum which threatens to overrun the place. We found 20 of the planted 



36 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



specimens dead among the material gathered on this date, and we 
thought it possible that this might be due to the too luxuriant growth 
of Sesuvium, and therefore deemed it best to move the colony. We 
placed 225 living specimens near the southern part of the westerly one 
of two foundation walls north of the cistern, and marked the situation 
with a stake. 

On April 22, 1914, this new colony was still in force, but we were 
unable to find any young individuals. The old planting was completely 
overrun with rank vegetation, even more rank than on the previous 
year; in fact it was impossible to determine if any specimens had sur- 
vived. 

In May 1916 the Cerions were doing well at both plantings. We 
gathered 18 adult living specimens of the first generation of Florida- 
grown individuals and 31 of those originally imported at the second 
planting. The Florida-grown individuals were measured and marked 
and placed about 5 feet east of the stone wall, which is a remnant of a 
house on the east end of the key, while we replanted the Bahama 
material a little west of the center of the second stone wall. 

The original planting, which was completely swamped by a rank 
growth of vegetation during the past two years, seemed to have sur- 
vived quite well. This year the drought was so great that the grass was 
dried up to a large extent. Even the cacti had a shriveled appearance 



Table No. 


19. — Measurements of the first generation of Florida-grown Cerion casablancoe 








from Indian Key. 












Measurements 






Measurements 






Measurements 


Serial 


No. of 


of shells. 


Serial 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


No. 


whorls. 




No. 














Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






m?w. 


mm. 






mm. 


mm. 


1 


10.8 


28.0 


12.7 


8 


10.2 


26.1 


12.9 


15 


10.2 


27.0 


11.8 


2 


11.0 


31.0 


13.0 


9 


9.8 


28.4 


13.8 


16 


10.2 


27.0 


13.5 


3 


10.6 


28.4 


13.0 


10 


10.6 


27.3 


12.3 


17 


10.3 


27.0 


12.3 


4 


11.3 
10.2 


29.0 
27.5 


13.3 
12.2 


11 
12 


10.4 
10.2 


26.0 
24.0 


12.8 
13.0 


18 


11.0 


29.0 


12.3 


5 










6 


10.0 


25.3 


12.2 


13 


10.4 


27.0 


12.1 


Average . 


10.5 


27.45 


12.72 


7 


10.5 


29.1 


12.8 


14 


11.3 


27.0 


13.0 


Greatest. 
Least . . . 


11.3 

9.8 


31.0 
24.0 


13.8 
11.8 



and this enabled us to discover 29 of the originally planted Cerions, 
49 adult Florida-grown individuals, and 15 tips. We planted the 
Florida-grown individuals in one place at the inner edge of the grass, 
about 45 feet east and a httle to the left of the stone wall, looking land- 
ward. 

In 1917 and 1918 this colony was not visited. 

On January 21, 1919, when we again visited Indian Key, the old 
plantation was completely swamped with a growth of Sesuvium, 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



37 



Uniola paniculata, and cacti. The planting in the interior was in even 
worse condition, for, in addition to the cacti and other rank vegetation, 
a complete invasion of huge agaves covered the territory and made it 
literally impossible to move about except where one actually cut a path 
through the bayonet-like agave leaves. We were therefore unable to 
secure any material of the second generation from this colony. 

The Colony on Bahia Honda Key. 

On June 2, 1912, we placed 500 specimens of Cerion casablancoe on the 
northeast side of the deep cut which runs parallel with the outer beach. 
The ground supported a scattered growth of palmetto and grass. 

On April 22, 1913, the place was completely overrun with sand spurs, 
Cenchrus echinatus, in full fruit, which made a search for moUusks a 
trying task. 

On April 23, 1914, we found 10 adult specimens and 3 nearly adult 
of the first generation of Florida-gro^vn individuals. The measure- 
ments are shown in table 20 and the figures of the specimens are shown 
on plate 5 of the 1915 report. 

On April 26, 1915, the colony was visited again and 58 full-grown 
individuals of the first Florida-grown generation and 23 ranging from 
quarter-grown to almost full-grown were found. Most of these speci- 



Table No 


20. — Measurements o 


f the first generation of Florida-grown Cerion casablancoe 






from Bahia Honda Key. 






Measurements 






Measurements 






Measurements 


Serial 


No. of 


of shells. 


Serial 


No. of 


of shells. 


Serial 


No. of 


of shells. 


No. 


whorls. 






No. 


whorls. 






No. 


whorla. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1* 


11.0 


31.5 


13.5 


6 


10.5 


31.0 


14.4 


Average . 


10.67 


29.71 


13.30 


2** 


11.0 


32.8 


13.4 


7 


11.0 


30.2 


13.2 


Greatest. 


11.0 


32.8 


14.4 


3 


10.3 


29.0 


13.3 


8 


10.4 


25.5 


12.1 


Least . . . 


10.3 


24.5 


12.1 


4 


10.8 


29.8 


13.2 


9 


10.4 


24.5 


13.5 










5 


10.7 


33.0 


13.5 


10 


10.6 


29.8 


13.0 











* Length estimated. 



** Shell not quite adult. 



mens were in the ditch. The material on top of the flat seemed to have 
been completely wiped out by a destructive fire that had swept part of 
the key. We marked and measured 56 and planted 55 of them. For 
measurements see table 21 and for figures see plates 36 and 37. 

On May 20, 1916, we again visited Bahia Honda Key and found 22 
full-grown specimens of the first Florida-grown generation; some of 
these were fully 150 feet from the stake where they were originally 
planted. Not a single specimen of the originally transplanted material 
was evident and it seems as if all of these had perished in the fire of 
1915 to which we have referred. In 1916 the snails were largely con- 
fined to the inner edge of the ditch. The colony of Florida-grown 



38 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



individuals planted on the seaward side of the ditch seemed to have 
become completely lost in the very rank and dense growth of Uniola 
paniculata. It will be necessary to cut this down before a report can 
be made on this colony. 



Table No 


21. — Measurements of the first generation 


of Florida-grown Cerion casahlancce 










from 


Bahia Honda Key. 














Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 






1 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






m,m. 


mm. 






mm. 


7nm. 


1 


11.1 


26.9 


12.9 


21 


11.0 


29.5 


13.2 


41 


10.3 


27.3 


13.0 


2 


10.3 


27.0 


13.0 


22 


10.4 


25.5 


12.7 


42 


10.9 


29.5 


13.1 


3 


11.2 


31.2 


12.9 


23 


11.0 


30.7 


12.9 


43 


10.5 


28.2 


14.2 


4 


10.8 


27.0 


12.8 


24 


10.3 


28.0 


14.0 


44 


11.0 


30.0 


12.5 


5 


10.4 


26.8 


12.2 


25 


10.6 


27.0 


12.6 


45 


11.2 


30.2 


13.5 


6 


10.5 


29.2 


12.5 


26 


10.8 


27.6 


11.9 


46 


11.3 


31.0 


12.5 


7 


11.0 


30.0 


13.3 


27 


10.5 


27.8 


12.5 


47 


11.2 


31.5 


14.2 


8 


10.9 


28.7 


12.6 


28 


11.2 


28.9 


12.5 


48 


11.0 


29.0 


12.8 


9 


9.9 


27.0 


14.0 


29 


11.0 


28.3 


12.2 


49 


10.6 


27.0 


12.8 


10 


11.4 


27.7 


13.5 


30 


10.9 


32.7 


13.4 


50 


10.6 


25.5 


13.0 


11 


10.6 


28.7 


13.6 


31 


10.8 


27.1 


13.2 


51 


10.4 


25.1 


12.0 


12 


11.4 


29.8 


13.0 


32 


10.3 


28.4 


13.0 


52 


10.8 


28.2 


12.8 


13 


11.1 


30.5 


13.5 


33 


11.0 


28.0 


12.9 


53 


10.4 


28.0 


12.2 


14 


11.0 


28.0 


12.2 


34 


10.3 


28.3 


13.0 


54 


10.8 


29.0 


14.0 


15 


10.9 


29.0 


12.5 


35 


10.5 


25.5 


11.9 


55 


10.7 


27.0 


12.8 


16 


10.6 


28.0 


12.9 


36 


10.4 


27.0 


13.0 


56 


11.2 


30.5 


12.7 


17 

18 


10.8 
10.5 


27.0 
27.2 


12.6 
13.9 


37 
38 


11.2 
10.5 


32.0 
26.3 


14.0 
12.6 










Average . 


10.76 


28.4 


12.96 


19 


11.2 


28.1 


12.3 


39 


10.6 


29.0 


13.1 


Greatest. 


11.4 


32.7 


14.2 


20 


10.5 


29.0 


13.6 


40 


10.6 


29.2 


13.5 


Least . . . 


9.9 


25.1 


11.9 



Bahia Honda was not visited in 1917 or 1918. 

On January 20, 1919, the planting along the sides of the ditch was 
doing well, and also that on the sea side of the ditch, but we were not 
certain whether the unmarked specimens here consisted of second 
generation Florida-grown material or whether these might be first- 
generation specimens which had crossed the ditch. It seemed as if the 
ditch might have been crossed, judging from specimens found in such 
locations. We were therefore unable to give these any status or to 
make a positive statement regarding the second generation on Bahia 
Honda. 

Colonies of Cerion Casablanca on Loggerhead ICey. 

On this key seven plantings have been made of this species. These 
represent the Cerion colonies A, B, C, H, I, J, and 0. 

The Loggerhead ICet Colo^tt A. 

The first planting of Cerion casahlancce was made on June 8, 1912, 
when 500 specimens were placed in a meadow covered with a sparse 
growth of Sporoholus virginicus, Cyperus hrunneus, and cacti on the 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



39 



east side of the path, 600 feet north of the Ughthouse. This colony- 
was marked by a stake bearing the legend: "Cerions, 1912, A." 

In May 1913 our animals were doing well and without much diffi- 
culty we discovered 82 young, one having as many as 7 postnuclear 
whorls. The cacti seemed to be making altogether too much progress 
in their invasion of this field, so we thinned them out materially. 

In April 1914 we easily gathered 615 young in various stages of 
growth, from mere nepionic tips to adults; 20 adult of the first genera- 
tion were figured in the 1915 report, plate 2, top and bottom rows, as 
well as a lot of young on plate 4 and bottom figure of plate 5. The 100 
specimens represented on the lower figure of plate 5 were marked and 
planted as colony 6, while the 500 tips represented on plate 4 formed 
the initial planting of Colony B. The 20 adult specimens were fully 
discussed in the 1915 report. 



Table No 


22. — Measurements o 


f the first generation of Florida-grown Cerion casablancoe 




from Loggerhead Key Colony A. 








Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


Serial 


No. of 
whoris. 


of shells. 




1 


No. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm . 






mm. 


m.m. 


1 


11.4 


30.1 


12.3 


9 


11.6 


30.2 


12.0 


16 


10.9 


26.3 


11.0 


2 


11.1 


29.0 


12.0 


10 


11.5 


28.1 


12.3 


17 


11.2 


27.2 


11.8 


3 


10.5 


31.7 


13.6 


11 


11.2 


*27.8 


11.8 


18 


10.4 


26.5 


12.8 


4 


12.0 


34.0 


12.3 


12 


11.9 


28.2 


12.5 


19 


10.6 


26.0 


12.0 


5 


10 6 


32.0 

28.1 


14 5 


13 
14 


11 1 


26.5 
25.0 


12.8 
11.3 










6 


11.3 


11.7 


10.5 


Average . 


11.17 


28.80 


12.28 


7 


11.4 


31.2 


13.0 


15 


11.1 


28.0 


11.5 


Greatest. 


12.0 


34.0 


14.5 


8 


11.9 


31.4 


12.1 










Least. . . 


10.4 


25.0 


11.0 



* Altitude estimated; shell not adult. 

In June 1915 we re-examined this colony and found it doing exceed- 
ingly well. It had spread materially ; adults and young were seen every- 
where within a radius of 50 feet from the stake marking the spot where 
the planting was first made. Some of the moUusks had taken to the 
fringe of bay cedars and had even crossed the path and were in the 
bushes at the western end of it, but preferred the grass in the shade of 
the shrubs. In 1914 we had placed 162 of the originally planted mate- 
rial at the base of the stake. Of these, we found 56 dead in 1915. The 
removing of the epiphragm and replanting them during the bright part 
of the day may have affected them adversely, and while we were easily 
able to find 217 adult and 47 young Florida-grown individuals in this 
colony, we refrained from measuring them because we feared that they 
might represent a mixture of first and second Florida-grown genera- 
tions, so we allowed them simply to remain as they were. 

In 1916, 1917, and 1919 this colony was found in a most flourishing 
condition. When visited in January 1919 the ground everywhere was 
covered with adult and young. They had crossed the path and entered 



40 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



among the bay cedars on the west side of the path, where they seemed 
to be thriving well. This we considered rather unusual, for our previous 
experience had been that they commonly avoided the ground occupied 
by bay cedars or the dead leaves of these plants. The region occupied 
by Colony A at present seems to be as densely populated as was the 
original home in the Bahamas. 

The Loggerhead Key Colony B. 
On June 27, 1914, Colony B was started with 500 tips (see plate 4 
of the 1915 report), which were offsprings of Colony A. These were 
placed 150 feet distant and a little south of east of the stake which 



Table No 


23. — Measurements of the first generation 


of Florida-grown Cerion casablancce 








from Loggerhead Key Colony B. 














Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whoris. 


of shells. 


Serial 


No. of 


of shells. 








No. 


whorls. 










Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


11.2 


28.1 


12.0 


43 


11.4 


29.3 


12.1 


85 


10.7 


27.5 


11.6 


2 


11.3 


28.5 


11.5 


44 


11.7 


31.5 


12.2 


86 


11.8 


28.4 


10.9 


3 


10.9 


30.3 


12.4 


45 


11.4 


31.2 


12.9 


87 


10.2 


26.3 


12.4 


4 


10.7 


29.0 


12.1 


46 


11.2 


28.7 


11.9 


88 


10.8 


26.2 


11.0 


5 


10.9 


27.2 


12.0 


47 


10.4 


25.3 


11.0 


89 


11.4 


32.0 


12.4 


6 


11.7 


30.2 


11.9 


48 


11.2 


29.0 


12.0 


90 


11.0 


30.8 


12.4 


7 


11.1 


28.6 


12.0 


49 


11.5 


27.8 


11.1 


91 


10.8 


28.5 


12.2 


8 


10.6 


27.1 


11.4 


50 


10.1 


27.3 


13.0 


92 


11.4 


30.0 


12.5 


9 


10.7 


27.2 


11.6 


51 


11.1 


27.8 


10.8 


93 


10.1 


22.3 


10.2 


10 


11.2 


30.0 


12.6 


52 


11.1 


26.5 


11.2 


94 


10.1 


27.5 


11.8 


11 


10.8 


29.6 


12.7 


53 


11.8 


30.3 


11.7 


95 


10.5 


28.4 


12.9 


12 


11.0 


30.9 


12.0 


54 


11.3 


31.0 


12.1 


96 


10.8 


26.0 


10.8 


13 


11.2 


31.3 


12.8 


55 


11.4 


30.0 


11.5 


97 


10.6 


29.0 


12.5 


14 


11.1 


30.0 


12.4 


56 


11.2 


29.5 


12.9 


98 


11.0 


27.6 


12.7 


15 


11.2 


31.1 


11.4 


57 


11.0 


27.8 


12.1 


99 


10.9 


30.7 


12.9 


16 


11.2 


29.1 


11.7 


58 


10.1 


27.5 


11.5 


100 


10.5 


26.3 


10.9 


17 


10.7 


27.3 


12.5 


59 


11.1 


30.5 


11.8 


101 


11.0 


27.8 


11.0 


18 


10.7 


27.4 


11.6 


60 


11.1 


28.0 


11.1 


102 


10.8 


29.2 


13.0 


19 


10.6 


26.0 


11.6 


61 


10.6 


26.7 


12.1 


103 


10.9 


27.5 


10.6 


20 


10.9 


30.1 


12.0 


62 


10.1 


28.2 


12.3 


104 


10.9 


26.9 


11.2 


21 


11.5 


31.0 


11.1 


63 


10.2 


26.5 


12.1 


105 


11.1 


26.4 


11.3 


22 


10.5 


27.0 


11.6 


64 


10.3 


25.7 


11.1 


106 


12.0 


29.0 


11.7 


23 


11.0 


26.0 


10.7 


65 


10.2 


24.7 


11.9 


107 


10.5 


27.6 


11.9 


24 


11.0 


29.0 


12.0 


66 


10.8 


27.4 


12.5 


108 


10.4 


26.0 


11.4 


25 


11.2 


28.9 


11.5 


67 


11.8 


30.7 


12.3 


109 


10.8 


26.6 


11.0 


26 


10.5 


26.5 


11.7 


68 


10.9 


27.8 


11.6 


110 


10.9 


26.5 


10.9 


27 


10.8 


26.0 


11.6 


69 


11.2 


29.5 


12.1 


111 


10.2 


23.7 


11.0 


28 


10.8 


25.3 


11.0 


70 


11.1 


29.1 


12.0 


112 


9.5 


27.0 


11.7 


29 


10.5 


27.7 


11.2 


71 


10.9 


29.6 


12.7 


113 


11.2 


31.6 


12.0 


30 


10.8 


31.0 


12.5 


72 


10.1 


24.7 


11.2 


114 


11.8 


28.7 


12.0 


31 


11.1 


28.9 


11.2 


73 


11.0 


26.1 


11.6 


115 


10.3 


26.5 


12.0 


32 


11.4 


30.6 


12.1 


74 


11.2 


27.5 


11.4 


116 


10.6 


27.8 


11.5 


33 


11.4 


27.6 


10.7 


75 


10.6 


28.2 


12.3 


117 


10.8 


29.1 


11.8 


34 


10.0 


27.2 


12.3 


76 


10.4 


26.7 


11.8 


118 


10.6 


26.0 


11.5 


35 


10.5 


28.7 


12.0 


77 


10.8 


27.0 


11.5 


119 


10.6 


28.6 


11.9 


36 


11.8 


30.0 


12.1 


78 


10.2 


25.0 


11.0 


120 


10.7 


26.8 


11.8 


37 


10.7 


29.6 


11.9 


79 


10.8 


29.5 


12.7 


121 


10.6 


27.4 


11.6 


38 


11.9 


30.4 


12.0 


80 


10.4 


28.0 


12.3 


122 


10.8 


26.5 


11.0 


39 


10.8 


28.7 


12.0 


81 


10.5 
10.4 


27.0 
24.3 


12.7 
11.0 










40 


11.2 


30.6 


12.8 


82 


Average . 


10.87 


28.11 


11.82 


41 


10.7 


29.2 


12.2 


83 


10.7 


27.1 


12.2 


Greatest. 


12.0 


32.0 


13.0 


42 


10.9 


27.7 


12.9 


84 


11.1 


26.7 


11.5 


Least . . . 


9.5 


22.3 


10.2 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



41 



marked the original planting. They were in the southeast corner of 
the same meadow in which the original planting was made, in condi- 
tions apparently identical with those prevailing in the territory occu- 
pied by Colony A. The place is marked with a stake bearing the 
legend ''Cerions X." 

On June 28, 1915, we recovered 122 full-grown and 17 immature 
specimens from this colony; these we measured, marked, photographed, 
and planted in a new location as Colony J, which see. Their measure- 
ments are given in table 23 and their photographs are shown on plates 
38 to 41. 

In May 1916 we gathered 73 adults of the first generation of Florida- 
grown individuals. Measurements of these are given in table 24, the 
specimens are figured on plates 42 and 43. 

Table No. 24. — Measurements of the first generation of Florida-grown Cerion casablancce 
from Loggerhead Key Colony B. 







Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Alt. 


Diam. 


Alt. 


Diam. 


Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


11.3 


28.8 


12.3 


27 


11.3 


29.0 


12.0 


53 


10.7 


27.7 


11.8 


2 


11.5 


30.0 


13.5 


28 


10.5 


27.5 


13.0 


54 


10.3 


27.3 


12.5 


3 


10.7 


27.6 


13.1 


29 


11.0 


27.5 


12.5 


55 


11.6 


31.5 


12.8 


4 


10.6 


27.7 


13.5 


30 


11.7 


29.1 


11.5 


56 


11.4 


31.4 


13.0 


5 


10.7 


28.0 


12.0 


31 


11.7 


30.0 


12.0 


57 


10.8 


29.5 


12.3 


6 


11.3 


32.2 


13.0 


32 


10.8 


27.1 


12.1 


58 


10.8 


30.0 


12.5 


7 


11.0 


29.2 


13.0 


33 


10.2 


27.4 


13.0 


59 


11.4 


29.0 


12.5 


8 


11.2 


30.0 


12.4 


34 


11.1 


27.8 


12.3 


60 


10.9 


30.8 


13.7 


9 


11.0 


28.8 


12.5 


35 


11.8 


31.5 


12.3 


61 


10.4 


28.5 


13.0 


10 


11.4 


31.5 


13.1 


36 


11.0 


30.0 


13.2 


62 


10.9 


27.9 


12.5 


11 


10.1 


25.5 


12.4 


37 


10.1 


23.2 


12.2 


63 


11.0 


29.0 


12.3 


12 


11.5 


28.5 


12.0 


38 


10.2 


28.3 


12.7 


64 


10.1 


29.5 


13.1 


13 


10.7 


28.0 


12.9 


39 


11.0 


32.7 


13.9 


65 


11.2 


29.7 


12.0 


14 


10.4 


26.2 


13.0 


40 


10.7 


28.2 


12.5 


66 


11.3 


30.0 


11.8 


15 


11.4 


30.2 


13.1 


41 


11.2 


29.2 


11.5 


67 


10.8 


27.7 


13.0 


16 


10.7 


28.0 


12.5 


42 


12.0 


31.2 


13.0 


68 


11.0 


29.6 


12.0 


17 


10.9 


29.0 


12.2 


43 


10.2 


25.7 


12.0 


69 


11.2 


29.2 


12.3 


18 


11.0 


29.0 


12.5 


44 


11.2 


29.3 


13.0 


70 


10.7 


27.0 


12.4 


19 


11.1 


31.0 


13.8 


45 


10.1 


26.7 


12.1 


71 


11.1 


26.6 


11.5 


20 


12.4 


34.4 


14.0 


46 


11.6 


26.7 


11.8 


72 


11.3 


29.5 


13.2 


21 


10.6 


26.4 


13.5 


47 


11.0 


27.7 


12.5 


73 


11.0 


27.7 


11.6 


22 
23 


10.6 
10.7 


29.2 
28.6 


13.2 
12.5 


48 
49 


10.2 
11.3 


25.0 
29.4 


12.5 
12.7 


Average . 








10.96 


28.7 


12.59 


24 


11.1 


27.4 


12.3 


50 


10.7 


26.9 


12.3 


Greatest. 


12.4 


34.4 


14.0 


25 


10.7 


28.0 


12.7 


51 


10.9 


28.3 


12.8 


Least . . . 


10.1 


23.2 


11.5 


26 


11.3 


30.0 


13.1 


52 


10.6 


27.2 


12.1 











Loggerhead Key Colony C. 
On June 27, 1914, we planted 100 marked immature specimens of the 
first generation of Florida-grown individuals from Colony A, on the 
west side of the path between the laboratory and the lighthouse, about 
135 feet south of the stake marking Colony A. This planting was in 
the northeast corner of a large meadow bearing a tag with the legend 
''Cerions Y." 



42 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



On June 27, 1915, we recovered 36 adults, which were measured, 
photographed, and replaced. The measurements can be seen in table 
25 and the specimens are depicted on plate 44. 



Table No 


25. — Measurements of the first generation 


of Floridcv-grown 


Oerion casablancce 








from Loggerhead Key Colony C. 












Measurements 






Measurements 






Measurements 


Serial 


No. of 


of shell. 


Serial 
No. 


No. of 
whorls. 


of shell. 


Serial 
No. 


No. of 
whorls. 


of shell. 


No. 


whorls. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


m,m. 






7nm. 


mm. 


1 


10.8 


26.2 


10.0 


15 


11.0 


28.0 


12.0 


29 


10.5 


27.3 


12.3 


2 


11.0 


27.4 


11.1 


16 


10.9 


31.5 


12.1 


30 


10.8 


25.7 


10.5 


3 


11.0 


28.5 


12.0 


17 


11.4 


30.0 


12.4 


31 


11.0 


28.5 


12.5 


4 


11.8 


30.2 


11.9 


18 


10.1 


24.3 


11.2 


32 


11.2 


27.5 


11.6 


5 


11.1 


26.1 


11.2 


19 


10.3 


25.5 


11.1 


33 


11.4 


28.3 


11.5 


6 


10.8 


29.6 


12.2 


20 


10.6 


27.0 


11.9 


34 


11.4 


26.5 


11.1 


7 


10.8 


29.7 


13.1 


21 


10.7 


28.0 


12.0 


35 


11.2 


30.6 


12.0 


8 


10.1 


30.0 


13.1 


22 


10.7 


27.7 


11.8 


36 


10.8 


30.0 


12.6 


9 


10.7 


26.9 


11.4 


23 


11.2 


28.4 


11.6 
















10 


10.5 


26.8 


11.6 


24 


10.1 


27.3 


13.0 


Average . 


10.9 


28.26 


11.83 


11 


10.8 


28.2 


11.3 


25 


10.8 


26.5 


12.5 


Greatest. 


11.8 


31.9 


13.1 


12 


10.7 


27.9 


11.6 


26 


11.0 


31.3 


12.8 


Least . . . 


10.1 


24.3 


10.0 


13 


11.5 


30.9 


11.4 


27 


10.9 


28.8 


12.3 










14 


11.8 


31.9 


11.4 


28 


11.1 


28.3 


11.7 











In May 1916 we added to this colony 73 adults of the first-grown 
Florida generation from Colony B, and also the 7 living specimens from 
Colony J. 

In July 1917 we found 9 specimens of the second generation. 

In 1918 the colony was not visited, but in January 1919 we found 
100 adult specimens of the second generation from this colony. Meas- 
urements of these are shown in table 26 and figures thereof are given 
on plates 45-47. These specimens, together with 25 tips of the second 
generation, w^ere planted as Colony O. (See page 43.) 

The Loggerhead Key Colonies H and I. 
These are discussed under Colonies H and I of Cerion viaregis. 
(See pages 25 and 26.) 

The Loggerhead Key Colony J. 

In June 1915 we placed 122 adult and 14 immature Florida-grown, 
first-generation Cerions in a httle clearing on the east side of the path, 
halfway between the laboratory and Colony A. The place was marked 
by a stake and a tag bearing the legend "Cerions, 1915, J." 

In May 1916 we recovered 121 of these, but all except 7 were dead. 
They had not left the region about the stake where we had dropped 
them. It is probable that our planting them during the heat of the 
day with their epiphragm broken may have had this disastrous effect. 
The 7 hving specimens were placed with Colony C. 

No specimens were observed in 1917, but in January 1919 we found 
a few in the region of this planting, which goes to show that it is never 
quite safe to say that a colony is extinct. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



43 



Table No. 26. — Measurements of the second generation of Florida-grown Cerion casablancoe 

from Loggerhead Key Colony C. 







Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shell. 


Serial 

No. 


No. of 
whoris. 


of shell. 


Serial 
No. 


No. of 


of shell. 


Alt. 


Diam. 


Alt. 


Diam. 


whoris. 


Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


10.9 


27.3 


13.2 


36 


10.1 


27.1 


13.0 


71 


9.8 


26.7 


12.5 


2 


11.0 


27.9 


14.1 


37 


10.3 


28.1 


14.0 


72 


10.3 


27.0 


14.6 


3 


11.4 


30.2 


13.4 


38 


10.3 


24.2 


11.6 


73 


11.1 


27.3 


12.3 


4 


12.1 


30.0 


13.0 


39 


11.2 


25.7 


12.1 


74 


10.7 


28.3 


13.7 


5 


10.6 


28.0 


13.7 


40 


11.2 


26.7 


13.5 


75 


9.9 


23.5 


12.2 


6 


11.2 


28.9 


12.2 


41 


10.5 


26.2 


14.6 


76 


11.3 


28.5 


12.5 


7 


11.1 


28.3 


12.6 


42 


11.1 


29.1 


13.5 


77 


11.1 


28.1 


13.7 


8 


11.1 


27.5 


12.7 


43 


11.4 


27.4 


13.5 


78 


10.6 


24.5 


12.7 


9 


11.5 


30.1 


14.0 


44 


10.8 


29.3 


12.5 


79 


10.6 


27.4 


13.3 


10 


10.7 


26.5 


13.4 


45 


11.1 


27.8 


13.7 


SO 


11.1 


29.1 


12.5 


11 


10.7 


27.8 


13.0 


46 


11.3 


29.0 


14.4 


81 


10.3 


24.5 


12.7 


12 


10.1 


24.2 


12.5 


47 


11.1 


27.8 


13.7 


82 


11.1 


27.6 


13.6 


13 


10.9 


28.4 


12.7 


48 


11.0 


28.0 


13.3 


83 


11.0 


27.5 


12.1 


14 


10.8 


26.2 


13.1 


49 


10.0 


25.6 


14.8 


84 


10.6 


28.3 


12.7 


15 


11.4 


27.5 


13.3 


50 


11.2 


27.6 


13.4 


85 


11.6 


28.5 


12.0 


16 


10.2 


27.5 


13.7 


51 


10.8 


25.9 


13.0 


86 


10.2 


25.5 


13.2 


17 


10.6 


25.1 


12.2 


52 


10.5 


27.0 


13.0 


87 


10.9 


25.8 


11.8 


18 


11.2 


29.6 


14.0 


53 


10.5 


25.0 


11.9 


88 


11.5 


28.7 


12.9 


19 


11.4 


27.9 


11.8 


54 


10.1 


24.5 


12.7 


89 


11.0 


28.2 


13.7 


20 


11.5 


28.9 


14.0 


55 


10.7 


24.0 


12.7 


90 


11.1 


26.1 


11.5 


21 


10.2 


23.7 


11.3 


56 


11.0 


27.3 


12.0 


91 


10.6 


26.9 


13.2 


22 


10.3 


26.4 


12.8 


57 


10.0 


25.8 


12.5 


92 


11.1 


28.1 


13.5 


23 


11.1 


25.6 


12.3 


58 


10.6 


26.9 


12.4 


93 


10.6 


26.7 


13.1 


24 


11.4 


29.0 


12.3 


59 


9.9 


25.8 


13.5 


94 


10.6 


25.2 


12.5 


25 


11.3 


30.7 


14.0 


60 


10.7 


28.2 


12.7 


95 


10.4 


25.4 


12.0 


26 


11.7 


31.3 


14.2 


61 


9.7 


24.6 


12.1 


96 


11.4 


28.2 


13.2 


27 


10.8 


26.3 


11.7 


62 


11.6 


29.0 


13.0 


97 


11.4 


27.6 


12.7 


28 


10.8 


25.1 


10.1 


63 


10.9 


29.1 


13.0 


98 


11.1 


26.7 


12.6 


29 


11.2 


29.7 


13.0 


64 


10.4 


28.0 


13.0 


99 


9.8 


23.2 


11.8 


30 


11.5 


30.7 


13.0 


65 


10.8 


29.0 


13.2 


100 


10.4 


24.6 


11.3 


31 
32 


10.2 
11.0 


27.6 
27.2 


12.8 
12.6 


66 
67 


10.0 
10.8 


24.4 
28.2 


12.1 
12.8 


Average . 








10.83 


27.2 


12.91 


33 


11.1 


27.0 


12.8 


68 


10.7 


25.7 


12.7 


Greatest. 


12.1 


31.3 


14.8 


34 


12.0 


30.8 


14.0 


69 


11.0 


25.9 


13.1 


Least . . . 


9.7 


23.2 


10.1 


35 


10.2 


26.1 


13.0 


70 


11.1 


27.5 


13.5 











The Loggeehead Key Colony O. 
This colony was started January 14, 1919, and consists of 100 adult 
shells (figured on plates 45-47) whose measurements are given in table 
26, together wdth 25 tips of the second generation of Florida-grown 
individuals. They were taken from Colony C and were planted in a 
little meadow off the northeast comer of the laboratory. 



44 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



DISCUSSION OF THE DATA. 
First Generation of Florida-grown Cerion casablanc^. 

An examination of the first generation of Cerion casahlancoe grown 
on the various Florida keys reveals the fact that, so as far as type of 
structure is concerned, no deviation appears to have taken place 
beyond that found in material from the White House region of Andros. 
An analysis of the measurements of the first generation gives the results 
shown in table 27. 

Table No. 27. — First generation Floridorgrown Cerion casablancce. 



Colony, 



No. of 
whorls. 



Altitude. 



Greater 
diameter. 



No. of 
specimens. 



Averages: 

First Key north of Sands Key 

Indian Key 

Bahia Honda Key, 1914 

Bahia Honda Key, 1915 

Loggerhead Kej', Colony A 

Loggerhead Key, Colony B, 1915 

Loggerhead Key, Colony B, 1916 

Loggerhead Key, Colony C 

Average of all Florida-grown first 

generation 

Average of check series 

Greatest: 

First Key north of Sands Key 

Indian Key 

Bahia Honda Key, 1914 

Bahia Honda Key, 1915 

Loggerhead Key, Colony A 

Loggerhead Key, Colony B, 1915 

Loggerhead Key, Colony B, 1916 

Loggerhead Key, Colony C 

Greatest of all Florida-grown first 

generation 

Greatest of check series 

Least: 

First Key north of Sands Key 

Indian Key 

Bahia Honda Key, 1914 

Bahia Honda Key, 1915 

Loggerhead Key, Colony A 

Loggerhead Key, Colony B, 1915 

Loggerhead Key, Colony B, 1916 

Loggerhead Key, Colony C , 

Least of all Florida-grown first gener- 
ation 

Least of check series 



10.45 
10.50 
10.67 
10.76 
11.17 
10.87 
10.96 
10.90 



10.79 
10.92 



11.10 
11.30 
11.00 
11.40 
12.00 
12.00 
12.40 
11.80 



12.40 
12.10 



10.00 
9.80 

10.30 
9.40 

10.40 
9.50 

10.10 

10.10 



9.40 
10.00 



mm. 

28.31 

27.45 

29.71 

28.40 

28.80 

28.11 

28.70 

28.26 



28.47 
27.19 



32.00 
31.00 
32.80 
32.70 
34.00 
32.00 
34.40 
31.90 



34.40 
32.90 



24.00 
24.00 
24.50 
25.10 
25.00 
22.30 
23.20 
24.30 



22.30 
24.00 



mm. 

14.10 

12.72 

13.30 

12.96 

12.28 

11.82 

12.59 

11.83 



12.70 
13.70 



15.00 
13.80 
14.40 
14.20 
14.50 
13.00 
14.00 
13.10 



15.00 
15.60 



12.50 
11.80 
12.10 
11.90 
11.00 
10.20 
11.50 
10.00 



23 
18 
10 
56 
19 
122 
73 
36 



4463 



10.00 
11.00 



This analysis shows that we have a little larger range of variation in 
the first Florida-grown generation than in the check series from Andros 
Island, Bahamas. In the number of whorls the Florida-grown speci- 
mens vary from 12.4 to 9.4, while the check series varies from 12.1 to 10. 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



45 



In altitude our Florida-grown material varies from 34.4 mm. to 22.3 
mm. as against 32.9 mm. to 24 mm. in the check series. In diameter 
our Florida-grown specimens vary from 15 mm. to 10 mm., while in the 
check series the variation is from 15.6 mm. to 11 mm. These measure- 
ments, however, it should be remembered, cover 4,463 specimens and 
were we to examine a check series of equal size it is not at all improbable 
that these slight differences would also be present. In other words, 
the measurable characters show no decided change over anything that 
one might find in the Bahama material. 

Of the second generation of Florida-grown specimens we have so far 
obtained only 102 specimens. These, hke the first generation, show a 
little wider range of variation in measurements, but no differences in 
shell characters. The range of variation here is 12.1 to 9.7 whorls, 
while in the check series it is 12.1 to 10. In altitude the second gener- 
ation varies from 31.3 mm. to 23.2 mm. against 32.9 mm. and 24 mm. 
of the check series. In greater diameter the variation is 15 mm. to 
10.1 mm. against 15.6 mm. and 11 mm. We may therefore say that 
the summary remarks applying to the first generation also obtain here. 
Table 28 gives a httle more detailed account of this generation. 

Table No. 28. — Second generation Florida-grown Cerion casablancoe. 



Colony. 


No. of 
whorls. 


Altitude. 


Greater 
diameter. 


No. of 
specimens. 


Averages: 

First Key north of Sands Key 


10.60 
10.83 


7nm. 
28.95 
27.20 


mm. 

14.70 

12.91 


2 
100 


Loggerhead Key Colony C 


Average of all Florida-grown second 
generation 


10.71 
10.92 


28.07 
27.19 


13.80 
13.70 


102 


Average of check series 


Greatest: 

First Key north of Sands Key 


11.00 
12.10 


31.30 
31.30 


15.00 
14.80 




Loggerhead Key Colony C 


Greatest of all Florida-grown second 
generation 


12.10 
12.10 


31.30 
32.90 


15.00 
15.60 


Greatest of check series 


Least: 

First Key north of Sands Key 


10.20 
9,70 


26.60 
23.20 


14.40 
10.10 


Loggerhead Key Colony C 


Least of all Florida-grown second 
generation 


9.70 
10.00 


22.20 
24.00 


10.10 
11.00 


Least of check series 





Cerion Crassilabris ("Shuttleworth" Sowerby). 
The Loggerhead Key Colony L. 

In May 1915 Dr. Mayor collected a lot of specimens of Cerion crassi- 
labris, at Balena Point, near Guanico Bay, Porto Rico, 800 of which we 



46 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



planted in June of the same year in a little meadow on the west side 
of the south end of the island. The place of the planting is covered by 
a moderate growth of Uniola paniculata and is marked by a stake bear- 
ing a tag with the legend, "Porto Rico, 1915." 

The check series, consisting of 100 specimens. Cat. No. 334724 U. S. 
N. M., taken at random from the collection w^hich furnished the mate- 
rial planted on Loggerhead Key, yields the measurements shown in 
table 29. The specimens are figured on plates 48-50. 









Table No. 29. — Check series of Cerion crassilabris. 












Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


m7n. 






mm. 


mm. 






TTim. 


mm. 


1 


10.3 


27.5 


12.6 


36 


9.5 


22.0 


13.2 


71 


9.2 


21.3 


12.2 


2 


10.5 


25.8 


13.9 


37 


10.0 


22.1 


10.9 


72 


9.3 


21.2 


12.2 


3 


10.1 


25.1 


13.0 


38 


10.3 


23.2 


12.3 


73 


9.5 


21.1 


12.0 


4 


10.3 


25.0 


13.3 


39 


9.6 


22.1 


11.3 


74 


9.8 


20.6 


11.8 


5 


10.4 


25.2 


13.2 


40 


9.6 


22.6 


11.8 


75 


9.5 


20.5 


11.5 


6 


10.0 


25.0 


13.5 


41 


9.4 


22.0 


12.0 


76 


9.0 


20.2 


13.2 


7 


9.4 


24.0 


12.3 


42 


9.5 


22.0 


12.8 


77 


9.1 


21.1 


13.0 


8 


9.7 


24.2 


10.6 


43 


10.3 


23.2 


12.1 


78 


9.3 


21.5 


13.0 


9 


10.2 


25.4 


13.5 


44 


9.8 


22.2 


12.2 


79 


9.3 


21.3 


13.2 


10 


10.3 


25.0 


13.6 


45 


9.5 


22.1 


13.8 


80 


9.2 


21.0 


12.6 


11 


10.5 


23.5 


11.9 


46 


9.3 


22.0 


12.5 


81 


9.6 


21.0 


12.2 


12 


9.3 


22.1 


12.2 


47 


9.5 


22.6 


12.6 


82 


8.5 


20.0 


12.3 


13 


10.0 


24.0 


13.2 


48 


9.7 


22.0 


12.0 


83 


9.5 


21.2 


12.1 


14 


10.0 


23.5 


13.5 


49 


9.9 


21.3 


11.6 


84 


9.2 


21.3 


12.8 


15 


9.4 


24.0 


13.0 


50 


9.9 


22.5 


11.8 


85 


9.2 


20.9 


12.2 


16 


9.5 


24.0 


12.7 


51 


9.6 


22.7 


13.2 


86 


9.5 


21.5 


11.8 


17 


9.5 


23.0 


13.6 


52 


9.5 


22.2 


12.0 


87 


9.5 


21.2 


12.1 


18 


9.4 


24.2 


13.2 


53 


9.6 


22.5 


12.8 


88 


9.3 


21.0 


12.0 


19 


9.5 


23.8 


13.8 


54 


9.0 


21.0 


12.1 


89 


9.3 


20.4 


11.4 


20 


10.2 


23.1 


13.1 


55 


9.5 


21.5 


12.0 


90 


9.3 


20.5 


11.5 


21 


10.0 


23.0 


12.2 


56 


9.2 


21.1 


12.5 


91 


9.2 


19.4 


12.0 


22 


9.5 


22.7 


11.8 


57 


9.1 


20.8 


11.3 


92 


8.9 


19.6 


11.9 


23 


10.0 


23.6 


12.4 


58 


9.4 


22.0 


11.8 


93 


9.2 


20.2 


11.8 


24 


9.3 


22.4 


11.6 


59 


9.3 


20.5 


12.3 


94 


9.0 


19.6 


11.6 


25 


10.2 


23.6 


11.9 


60 


10.1 


21.2 


11.2 


95 


9.2 


19.3 


11.2 


26 


9.3 


23.2 


12.3 


61 


9.4 


21.5 


12.1 


96 


9.1 


20.1 


12.3 


27 


9.4 


23.2 


13.1 


62 


9.4 


21.2 


11.7 


97 


9.1 


19.8 


12.2 


28 


10.0 


23.5 


14.0 


63 


9.3 


21.6 


13.0 


98 


9.2 


19.9 


12.3 


29 


9.5 


23.0 


13.6 


64 


9.5 


22.0 


12.0 


99 


9.2 


19.0 


11.1 


30 


9.5 


24.0 


13.8 


65 


9.9 


22.0 


13.1 


100 


9.5 


20.5 


11.8 


31 


10.0 


23.1 


13.0 


66 
67 


9.5 
9.3 


21.0 
20.9 


10.5 
11.7 










32 


9^4 


22.9 


13*4 


Average . 


9.55 


22.13 


12.41 


33 


9.4 


22.6 


13.7 


68 


9.1 


20.3 


12.2 


Greatest. 


10.5 


27.5 


13.9 


34 


9.4 


23.7 


12.8 


69 


9.8 


21.1 


12.2 


Least . . . 


8.5 


19.0 


10.6 


35 


9.6 


23.5 


13.0 


70 


9.2 


21.3 


13.1 











EXPERIMENTS IN THE BREEDING OF CERIONS. 



47 



Table No. 


30. — Measurements of the first generation 


of Florida-grown Cerion crassilabris 








from Loggerhead Key Colony L. 












Measurements 






Measurements 






Measurements 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whoris. 


of shells. 


Serial 
No. 


No. of 

whorls. 


of shells. 
















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


9.9 


22.3 


11.0 


15 


9.4 


23.3 


10.6 


29 


9.9 


21.0 


9.7 


2 


10.1 


22.6 


9.9 


16 


9.1 


21.4 


10.2 


30 


9.6 


22.9 


10.6 


3 


10.0 


22.8 


10.8 


17 


9.2 


20.0 


10.0 


31 


9.6 


23.5 


10.8 


4 


9.9 


22.0 


9.7 


18 


9.3 


24.2 


10.9 


32 


9.3 


20.9 


10.6 


5 


10.0 


22.9 


11.0 


19 


8.8 


20.0 


10.5 


33 


9.0 


19.2 


9.9 


6 


9.0 


21.9 


10.3 


20 


9.6 


22.3 


11.0 


34 


9.9 


21.9 


10.6 


7 


9.7 


22.2 


10.6 


21 


9.1 


22.1 


10.3 


35 


9.3 


23.5 


10.6 


8 


9.8 


23.4 


10.1 


22 


9.4 


22.4 


10.3 


36 


9.5 


22.9 


10.6 


9 


Q 8 


99 8 


19 ^ 


23 


Q Q 


9*^ 7 


10.1 
10.0 










10 


10.0 


23.3 


10.3 


24 


9.4 


20.9 


Average . 


9.55 


22.29 


10.49 


11 


9.8 


23.0 


11.4 


25 


9.5 


21.8 


9.9 


Greatest. 


10.1 


25.4 


12.3 


12 


9.6 


23.5 


10.6 


26 


10.1 


25.4 


10.6 


Least . . . 


8.8 


19.2 


9.7 


13 


9.1 


21.4 


10.5 


27 


9.2 


21.4 


10.7 










14 


9.6 


22.3 


10.2 


28 


9.6 


21.4 


10.6 











The snails were doing well in May 1916. 

In July 1917 no adult specimens of the first generation were located. 

In January 1919 we obtained 36 adult and 4 almost adult individuals 
of the first generation, and many tips were in evidence at the base of 
tufts of grass. The 36 adult specimens were measured and their meas- 
urements are given in table 30, while the photographs of all the 40 are 
shown on plate 51. These 40 specimens form the basis of Colony S. 



The Loggerhead Key Colony S. 

This consists of 40 specimens of the first generation of Florida-grown 
Cerion crassilabris. They were planted in the northwest corner of the 
large meadow in which Cerion uva (Linnaeus) is located. The planting 
is fringed for a great part by bay cedars and the ground contains a good 
growth of Cyprus hrunneus, Sporoholus virginicus, and a scattered 
growth of cacti. The planting was marked by a stake bearing a tag 
with the legend: " Cerion, 1919, S." 

The measurements of the first generation of Florida-grown Cerion 
crassilabris fall completely within the range of variations noted for the 
check series excepting in the case of the least diameter, where the 
Florida-grown shells show several specimens with the diameter a frac- 
tion of a millimeter narrower than in the check series. 

A comparison of the figures (plate 51) with the check series will reveal 
that no appreciable change in outline or sculpture has taken place. 
We may therefore state that, as in the case of Cerion viaregis and Cerion 
casablancce, the changed environment to which we have subjected these 
specimens has not affected the progeny in any recognizable manner. 



48 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



Cerion uva (Linn^us) 
The Loggerhead Key Colony N. 

On May 25, 1916, we planted 8,317 of this species which had been 
gathered by Dr. Ralph Arnold on Curagao, Netherlands West Indies, 
in the southeastern end of the large central meadow in the southern end 
of the island. We first cleared the meadow of the abundant cactus 
growth. The ground here is largely fringed with bay cedars and cov- 
ered with a good growth of Sporoholus virginicus and Cyprus hrunneus. 

From the above-mentioned collection 100 specimens, taken at ran- 
dom. Cat. No. 334725, U. S. N. M., yield the measurements given in 
table 31. These specimens are figured on plates 52 and 53. 

In July 1916 large numbers of very small young were observed, but 
no adult Florida-grown individuals were present. 

In January 1919 we found numerous young, but not a single adult 
Florida-grown shell. 











Table No 


31. — Check series of Cerion uva. 












Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


12.2 


22.1 


10.0 


36 


11.1 


20.5 


10.6 


71 


11.9 


21.5 


9.5 


2 


12.0 


23.0 


11.0 


37 


11.3 


19.5 


10.0 


72 


10.8 


19.0 


9.5 


3 


12.1 


22.0 


10.1 


38 


11.0 


21.8 


11.0 


73 


11.8 


20.5 


10.0 


4 


13.0 


23.7 


11.0 


39 


11.0 


20.5 


10.0 


74 


11.9 


21.8 


10.2 


5 


11.9 


21.0 


10.2 


40 


12.1 


23.0 


10.0 


75 


11.0 


20.0 


10.2 


6 


11.0 


22.5 


10.0 


41 


11.5 


20.5 


10.1 


76 


11.0 


21.0 


10.4 


7 


11.8 


20.5 


9.0 


42 


11.7 


20.3 


10.0 


77 


11.5 


21.0 


10.0 


8 


11.1 


20.5 


11.0 


43 


11.3 


21.0 


11.0 


78 


11.0 


20.1 


9.1 


9 


10.0 


19.1 


9.5 


44 


11.9 


21.0 


10.5 


79 


11.6 


20.5 


9.5 


10 


11.5 


21.0 


10.0 


45 


10.5 


18.1 


10.0 


80 


11.0 


20.0 


9.5 


11 


12.5 


23.1 


10.2 


46 


11.5 


21.0 


10.0 


81 


12.5 


19.8 


10.5 


12 


12.5 


22.5 


10.1 


47 


10.5 


18.0 


9.5 


82 


11.9 


21.0 


10.8 


13 


11.0 


19.4 


10.5 


48 


11.5 


20.5 


10.2 


83 


10.8 


19.0 


10.0 


14 


12.1 


24.0 


10.4 


49 


11.5 


21.5 


10.5 


84 


11.9 


20.4 


10.0 


15 


12.5 


24.0 


11.0 


50 


11.6 


21,2 


9.3 


85 


11.2 


20,0 


10.0 


16 


10.8 


18.0 


10.0 


51 


12.0 


19.0 


10.0 


86 


11,0 


21,0 


9.3 


17 


11.7 


22.5 


10.0 


52 


12.1 


21.1 


10.0 


87 


10,9 


19.7 


10.0 


18 


11.1 


20.2 


11.0 


53 


11.0 


21.0 


10.3 


88 


11.8 


21.0 


9.5 


19 


12.0 


22.0 


10.0 


54 


11.1 


22.1 


10.5 


89 


12.5 


23.0 


10.5 


20 


11.0 


20.0 


10.2 


55 


10.8 


19.1 


10.0 


90 


12.0 


20.5 


9.4 


21 


10.9 


18.0 


9.0 


56 


10.9 


19.8 


10.1 


91 


11.5 


20,0 


10.0 


22 


12.0 


22.0 


9.5 


57 


11.2 


21.0 


10.0 


92 


11.3 


21,0 


9.5 


23 


12.8 


23.1 


9.9 


58 


11.9 


21.9 


9.9 


93 


11.9 


21,0 


9.0 


24 


11.9 


21.5 


11.0 


59 


11.6 


21.5 


9.1 


94 


11.0 


20.0 


10.3 


25 


11.9 


22.9 


9.4 


60 


11.0 


20.0 


10.0 


95 


11.0 


20.0 


10.3 


26 


10.0 


18.8 


10.4 


61 


11.9 


21.6 


10.0 


96 


11.8 


20.5 


10.0 


27 


12.0 


21.0 


9.0 


62 


10.8 


19.0 


9,3 


97 


10,9 


19.6 


9.5 


28 


12.0 


23.0 


11.6 


63 


11.5 


22.0 


10.0 


98 


12,5 


22.6 


9.6 


29 


12.2 


23.0 


10.0 


64 


10.7 


20.0 


9.0 


99 


11,8 


20.5 


9.5 


30 


12.8 


22.0 


10.0 


65 


11.3 


20.6 


10.0 


100 


10.9 


18.0 


10.0 


31 
32 


11.9 
11.9 


21.0 
23.0 


10.5 
11.0 


66 
67 


11.2 
10.7 


20.4 
19.0 


10.5 
9.9 










Average . 


11.5 


20.85 


10.04 


33 


10.9 


19.1 


10.5 


68 


10.7 


20.0 


10.0 


Greatest. 


13.0 


24.0 


11.6 


34 


11.0 


20.5 


11.0 


69 


11.5 


21.0 


9.5 


Least. . . 


10.0 


18.0 


9.0 


35 


11.9 


21.2 


10.7 


70 


11.5 


21.5 


10.0 











EXPERIMENTS IN THE BREEDING OF CERIONS. 49 

Cerion incanum (Binney) X Cerion viaregis Bartsch. 

I am sure that all naturalists who have prepared monographs upon 
large groups of animals have at times been puzzled how to treat 
systematically and how to account for some of the remarkably variable 
species which one occasionally finds. It usually happens that in a large 
genus almost all the forms are clearly defined and easily recognized 
specifically and there is never a question as to which species a given 
individual belongs. Now and then, however, one finds a group the 
members of which are readily recognized as closely related through some 
characteristic feature in spite of the fact that scarcely two individuals 
appear to be alike and that some of the extremes of these variants, 
were their character fixed, would demand a place in a different subgenus 
from that to which the norm of the group belongs (e. g., Odostomia 
(Evalea) virginalis Carpenter, from the West Coast of America). 
Usually this state of affairs is accompanied by the production of a large 
number of individuals; in fact, these variable forms are usually the 
dominant element in the region. Not only that, but as a rule we find 
that such forms are not confined to one faunal area, but appear to be 
able to extend their range over one or more of the adjacent areas. 
Organisms presenting such conditions have been said to be in a state of 
flux. It has been held by some that this variability is an expression of 
an effort on the part of a species to adjust itself to changing or changed 
environmental conditions, which, for the time being, affect it adversely. 
The followers of this hypothesis conceive that the organism, adversely 
struggling, is putting out an endless arraj^of feelers in the hope of finding 
a better way or better ways for continued existence. This hypothesis, 
while it may be true in some cases, does not seem to obtain in the varia- 
ble forms which have come under my observation, for it scarcely seems 
possible that the numerically and apparently physically dominant and 
most widely distributed form of a group in a certain region should be the 
one least suited to the environment in which it is existing. Prior to 
this year I was more and more inclined to the belief that we might 
possibly find that these very abundant and variable forms might repre- 
sent new ingressions into a faunal area in which conditions for their 
existence were optimum to an unusual degree, where the normal death 
rate, due possibly to an absence of natural enemies, might be reduced, 
and where all the factors involved were inclined to favor the new arrival 
to the utmost, and that these factors and the necessarily reduced 
in-breeding might be responsible for the loosening of specific bounds 
and the producing of variants which, in the course of time, might 
result in a state of flux. 

Our Cerion experiments on Newfound Harbor Key, however, throw 
a new light upon the case, for here we have produced a state of flux by 
cross-breeding. There is no question that if we did not know the true 
inwardness of the Cerion complex as it exists at the present time in our 



50 EXPERIMENTS IN THE BREEDING OF CERIONS. 

colony upon this key, we would treat the material as we have treated 
such assemblages in the past; that is, as a very variable species. It 
therefore seems proper to assume that the converse should receive an 
equally favorable consideration, for it seems fair to believe that further 
breeding experiments will prove that such complexes are the product 
of cross-breeding. 

The two species which have crossed here are very remotely related 
as can be readily seen by a comparison of plates 7, 8, 9, which represent 
the check series of Cerion viaregis from Bastian Point, Andros, and 
plates 54, 55, 56, which represent a check series of Cerion incanum — 
Cat. No. 334726, U. S. N. M.— from Porgee Key, Florida. The 
last-mentioned species is known to inhabit many of the keys from 
Virginia Key southwestward to the Marquesas Keys. A comparison 
of the anatomic structures shows even more striking characters of diver- 
sity, as shown on plates 1, 5, and 6, and discussed on pages 7 to 13 of 
this paper. The fact is, that it is very surprising that organisms pre- 
senting such great differences in organization should be able to cross 
at all, and it is still more remarkable that they should have produced 
fertile crosses. In this connection it should be recalled that our efforts 
to effect a cross between the Bahaman Cerion casablancce and Cerion 
viaregis proved unsuccessful. 

The offspring produced by this crossing show a remarkable range in 
variation, as can be readily seen by an examination of the 125 figures 
on plates 57, 58, and 59. This variation not only includes forms which 
appear near typical Cerion incanum and near typical Cerion viaregis 
and all grades of intermediates between these, but also forms that so 
closely resemble species of the Bahama mottled Cerion of the Cerion 
martensi group, that one not knowing their origin would unhesitatingly 
refer them to species of this complex occupying restricted areas in the 
Bahamas. Our crossing has evidently called to the surface submerged 
mottled Cerion strains present in Cerion viaregis and probably present 
in all the members of the complex that has been passing under the name 
of Cerion glans. 

The mixed elements vary in shape from the slender Cerion incanum 
type to the more or less cylindric Cerion viaregis, but a few of the speci- 
mens diverge entirely from this shape and assume the outline of the 
mottled Bahama Cerions. In ribbing they vary from the almost 
smooth Cerion incanum to the strongly costate Cerion viaregis. Forms 
having the shape of Cerion incanum may have the sculpture of 
Cerion viaregis, or the reverse may obtain. It should be mentioned 
here that the ribbing in the Bahama mottled Cerion falls between 
Cerion incanum and Cerion viaregis as far as strength goes, usually 
being a little nearer Cerion incanum in this respect. In coloration these 
specimens range from the color of Cerion incanum, which is white or 
sometimes finely vermiculated, to variously mottled, blotched, streaked 



EXPERIMENTS IN THE BREEDING OF CERIONS. 



51 









Table No. 32. — Check series of Cerion incanum. 












Measurements 






Measurements 






Measurements 


Serial 


No. of 

whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


No. 


1 












Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm. 






mm. 


mm. 






mm. 


mm. 


1 


12.4 


30.8 


13.8 


36 


11.8 


28.3 


12.7 


71 


11.2 


25.5 


12.9 


2 


11.5 


28.2 


13.6 


37 


11.8 


28.7 


13.0 


72 


10.6 


22.8 


12.0 


3 


11.5 


26.6 


12.2 


38 


11.3 


27.2 


12.0 


73 


11.0 


25.5 


12.3 


4 


11.2 


27.2 


12.6 


39 


11.5 


27.5 


12.5 


74 


11.1 


26.1 


14.4 


5 


10.7 


23.8 


14.0 


40 


11.6 


26.7 


12.1 


75 


10.9 


25.0 


13.2 


6 


10.2 


22.0 


12.0 


41 


10.9 


25.0 


13.1 


76 


10.8 


24.4 


13.9 


7 


11.9 


28.4 


13.6 


42 


11.0 


25.9 


12.8 


77 


10.6 


24.8 


13.2 


8 


11.5 


27.3 


12.5 


43 


10.8 


24.9 


13.7 


78 


11.1 


25.1 


12.5 


9 


11.3 


28.6 


12.9 


44 


11.0 


26.1 


13.2 


79 


10.8 


25.2 


12.5 


10 


11.4 


26.6 


12.2 


45 


10.8 


24.0 


13.2 


80 


10.9 


26.0 


13.2 


11 


11.4 


28.8 


13.4 


46 


11.4 


26.8 


14.0 


81 


11.1 


25.0 


12.8 


12 


11.5 


28.8 


13.3 


47 


11.6 


26.8 


13.0 


82 


10.6 


23.3 


13.5 


13 


11.5 


27.2 


13.0 


48 


11.5 


26.2 


13.0 


83 


11.2 


23.5 


11.7 


14 


11.3 


26.5 


12.2 


49 


10.5 


22.6 


12.3 


84 


11.3 


23.9 


13.2 


15 


11.9 


26.8 


13.6 


50 


11.6 


26.2 


13.4 


85 


11.2 


24.4 


12.2 


16 


12.0 


27.8 


13.2 


51 


11.3 


27.2 


13.8 


86 


11.3 


25.0 


13.2 


17 


11.2 


26.5 


13.6 


52 


11.4 


25.9 


12.8 


87 


10.5 


23.9 


13.2 


18 


11.1 


26.3 


12.4 


53 


10.8 


25.0 


12.8 


88 


10.2 


23.6 


13.0 


19 


11.1 


23.1 


11.6 


54 


11.2 


27.6 


13.6 


89 


11.1 


23.3 


12.3 


20 


11.8 


26.9 


12.9 


55 


10.4 


25.0 


12.2 


90 


11.2 


24.4 


13.1 


21 


11.5 


26.2 


13.8 


56 


11.1 


25.9 


13.9 


91 


11.0 


24.1 


12.7 


22 


11.9 


28.5 


12.5 


57 


10.8 


25.9 


12.9 


92 


11.0 


24.0 


12.9 


23 


10.6 


25.2 


13.5 


58 


11.6 


27.1 


13.9 


93 


10.8 


24.2 


13.2 


24 


10.0 


22.8 


11.5 


59 


10.9 


23.4 


12.2 


94 


10.8 


25.0 


13.2 


25 


11.4 


26.5 


12.8 


60 


11.1 


25.3 


13.5 


95 


10.6 


23.0 


11.5 


26 


11.3 


25.7 


12.0 


61 


10.6 


24.0 


12.0 


96 


10.5 


23.0 


11.5 


27 


11.5 


28.0 


13.3 


62 


10.7 


23.1 


12.2 


97 


10.9 


24.2 


12.3 


28 


10.9 


25.0 


12.5 


63 


10.5 


23.9 


13.5 


98 


10.5 


23.4 


11.6 


29 


11.1 


26.4 


13.0 


64 


10.9 


24.8 


13.0 


99 


10.5 


24.2 


14.0 


30 


10.4 


25.0 


13.0 


65 


11.0 


26.1 


13.3 


100 


10.5 


23.0 


12.1 


31 
32 


11.0 
11.1 


24.8 
25.5 


12.7 
12.0 


66 
67 


11.0 
11.6 


24.9 
27.0 


13.5 
12.6 










Average . 


11.09 


25.45 


12.83 


33 


10.9 


22.5 


11.6 


68 


10.5 


23.6 


12.0 


Greatest. 


12.4 


30.8 


14.4 


34 


11.2 


23.8 


12.1 


69 


11.8 


23.8 


11.8 


Least. . . 


10.0 


22.0 


11.5 


35 


10.9 


25.1 


12.0 


70 


11.0 


25.0 


12.9 











fulgurate with various shades of brown. Specimens with the outhne 
of typical Cerion incanum and Cerion viaregis may be strongly mottled 
and splashed with brown. Sometimes a specimen having the outline, 
sculpture, and external coloration of Cerion incanum shows the interior 
coloration of typical Cerion viaregis, and vice versa. 

Tables 32 and 33 give measurements of the check series of Cerion 
incanum and of the cross between Cerion viaregis and Cerion incanum, 
while table 34 gives a comparison of the summaries of Cerion viaregis, 
Cerion incanum, and Cerion viaregis X Cerion incanum. 

Table 34 shows that the cross between Cerion incanum and Cerion 
viaregis stands between the parent species, as far as number of whorls 
and measurements of altitude and diameter are concerned. The speci- 
mens figured on plates 57, 58, and 59, are now in my conservatory at 
Washington, where an attempt is being made to simulate the Florida 
environmental conditions, as far as it is possible to do so. We have 



52 



EXPERIMENTS IN THE BREEDING OF CERIONS. 







Table No. 33- 


—Cerion viaregis Bartsch X 


Cerion incanum Binney. 










Measurements 






Measurements 






Measurements 


Serial 
No. 


No. of 
whorls. 


of shells. 


Serial 

No. 


No. of 
whorls. 


of shells. 


Serial 
No. 


No. of 
whorls. 


of shells. 


















Alt. 


Diam. 






Alt. 


Diam. 






Alt. 


Diam. 






mm. 


mm,. 






mm. 


mm. 






mm. 


mm. 


1 


10.1 


24.5 


11.8 


44 


11.1 


25.0 


12.5 


87 


10.3 


22.9 


11.1 


2 


10.3 


23.7 


11.8 


45 


10.1 


22.3 


11.1 


88 


10.4 


22.9 


10.9 


3 


11.1 


24.5 


10.8 


46 


broken 


lip. 




89 


10.2 


21.8 


11.1 


4 


10.4 


23.3 


11.0 


47 


10.4 


20.5 


10.4 


90 


10.0 


20.0 


10.6 


5 


10.5 


24.2 


10.8 


48 


10.5 


22.2 


11.7 


91 


young. 






6 


10.4 


24.0 


10.3 


49 


11.2 


24.5 


10.5 


92 


broken 


lip. 




7 


11.3 


25.9 


12.1 


50 


11.2 


24.4 


12.1 


93 


broken 


lip. 




8 


10.1 


21.1 


11.0 


51 


10.3 


23.9 


12.3 


94 


10.2 


22.2 


10.7 


9 


10.6 


23.5 


10.8 


52 


10.5 


21.7 


11.2 


95 


10.3 


21.6 


11.9 


10 


10.2 


23.8 


11.3 


53 


9.6 


21.7 


10.2 


96 


11.2 


23.1 


12.8 


11 


broken 


lip. 




54 


10.4 


22.8 


11.2 


97 


9.3 


20.9 


11.4 


12 


10.3 


22.2 


11.1 


55 


10.5 


20.7 


11.4 


98 


broken 


lip. 




13 


broken 


lip. 




56 


broken 


lip — im 


mature. 


99 


10.9 


23.1 


11.1 


14 


10.2 


22.1 


11.4 


57 


11.0 


24.9 


11.7 


100 


young. 






15 


10.4 


22.2 


10.0 


58 


11.3 


24.5 


11.1 


101 


10.3 


21.4 


11.0 


16 


10.3 


20.9 


11.0 


59 


10.7 


23.2 


11.6 


102 


young. 






17 


10.2 


22.1 


10.7 


60 


11.1 


23.9 


11.6 


103 


young. 






18 


10.3 


22.6 


10.2 


61 


10.2 


22.4 


11.0 


104 


broken 


lip. 




19 


10.3 


22.4 


9.5 


62 


11.9 


24.5 


11.0 


105 


10.8 


23.1 


11.9 


20 


10.3 


22.7 


11.0 


63 


9.6 


20.5 


11.3 


106 


10.3 


22.6 


12.5 


21 


10.4 


23.3 


10.2 


64 


11.3 


24.2 


12.2 


107 


11.0 


23.5 


11.3 


22 


11.0 


24.0 


11.2 


65 


11.0 


23.7 


12.6 


108 


11.3 


24.0 


10.3 


23 


11.2 


24.9 


11.2 


66 


11.0 


24.8 


12.2 


109 


10.5 


21.4 


10.9 


24 


11.3 


24.2 


12.0 


67 


broken 


lip. 




110 


10.0 


21.1 


10.4 


25 


10.5 


22.8 


11.7 


68 


broken 


lip. 




111 


young. 






26 


11.2 


24.0 


11.6 


69 


10.6 


21.9 


10.9 


112 


young. 






27 


immat 


ure. 




70 


10.3 


22.4 


9.5 


113 


10.6 


21.8 


10.6 


28 


10.7 


21.8 


10.9 


71 


11.0 


24.1 


11.8 


114 


10.4 


21.8 


10.5 


29 


10.4 


22.1 


11.7 


72 


11.6 


28.4 


13.4 


115 


10.7 


22.7 


12.4 


30 


10.4 


22.0 


11.7 


73 


10.8 


24.8 


12.8 


116 


11.2 


21.2 


11.7 


31 


immat 


ure. 




74 


10.4 


22.7 


10.0 


117 


11.4 


23.3 


12.9 


32 


9.6 


19.5 


9.4 


75 


11.0 


23.4 


11.2 


118 


10.2 


22.0 


11.9 


33 


10.3 


21.7 


12.1 


76 


11.2 


25.0 


13.0 


119 


10.4 


21.2 


11.0 


34 


10.6 


22.8 


11.2 


77 


young. 






120 


10.8 


23.6 


11.0 


35 


10.1 


22.9 


11.9 


78 


10.5 


21.6 


12.3 


121 


10.7 


23.0 


11.1 


36 


10.6 


23.8 


11.9 


79 


10.8 


22.8 


10.3 


122 


10.7 


21.0 


10.9 


37 


10.3 


23.3 


11.0 


80 


10.1 


22.0 


10.7 


123 


10.8 


24.1 


12.2 


38 


10.5 


25.0 


11.7 


81 


11.1 


23.1 


10.7 


124 


young. 






39 


10.5 


22.3 


11.0 


82 


9.4 


19.1 


10.6 


125 


young. 






40 
41 


10.3 
10.4 


23.5 
24.1 


11.7 
12.1 


83 
84 


11.1 
10.0 


23.6 
19.2 


10.9 
10.0 










Average . 


10.57 


22.85 


11.27 


42 


10.5 


22.1 


11.3 


85 


10.1 


20.3 


9.4 


Greatest. 


11.9 


28.4 


13.4 


43 


11.6 


26.5 


12.7 


86 


10.4 


22.6 


11.1 


Least . . . 


9.3 


19.1 


9.4 



Table No. 34. 



Name. 


Averages, 


Greatest. 


Least . 


No. of 
whorls. 


Alti- 
tude. 


Greater 
diameter. 


No. of 
whorls. 


Alti- 
tude. 


Greater 
diameter. 


No. of 
whorls . 


Alti- 
tude. 


Greater 
diameter. 


Cerion viaregis 


10.08 
10.57 
11.09 


22.56 
22.85 
25.45 


11.13 
11.27 

12.84 


11.00 
11.90 
12.40 


27.00 
28.40 
30.80 


12.70 
13.40 
14.40 


9.10 

9.30 

10.00 


19.00 
19.10 
22.00 


9.00 

9.40 

11.50 


C. viaregis X C. incanum . 
Cerion incanum 



EXPERIMENTS IN THE BREEDING OF CERIONS. 53 

even obtained Florida key soil and plants in the hope of establishing 
the microflora upon which these forms seem to thrive and all efforts will 
be made to keep moisture and temperature conditions as near as possi- 
ble to the Florida standard. In this conservatory we have segregated 
pairs as nearly alike as possible, in order to determine, should we be 
successful in breeding these forms, if a fixation of characters might be 
effected and new species thus produced. 

In the Hght of the foregoing results the whole Cerion problem assumes 
a new aspect. One naturally wonders how this enormously diversified 
group may have been produced and from what source it was derived. 
To-day we know members of the genus from the Bahamas, where they 
are the dominant element in the molluscan fauna. It is here that the 
genus finds its greatest development. From the Bahamas they extend 
westward over the Florida Keys and probably over part of the southern 
tip of the mainland of Florida, then south over Cuba and its islets, the 
Isle of Pines, the Caymans, Haiti, Porto Rico, and the Virgin Islands. 
They appear to be absent from Jamaica and the Windward and Lee- 
ward group, but we again find them represented in Curagao by Cerion 
uva, and Cerion antoni (Kiister) has been described from Berbice, 
British Guiana. 

It is unfortunate that the geological history of the group is so incom- 
plete. At present the oldest-known member of the genus, Cerion 
anodonta Dall, comes from the Oligocene silex beds at Tampa, Florida. 
None of the Bahama fossil forms known are older than the Phocene. 
The absence of records from the Windward and Leeward Islands leaves 
a gap in our chain connecting with South America, the cradle of most of 
our West Indian land shells. Of course it is possible that Cerion, too, 
may have had its beginning in South America, for our knowledge of 
the derivation and distribution of other groups, shght as it seems, and 
the presence of Cerion antoni (Kuster) in British Guiana and of the 
stranded Cerion uva in Curasao, offer strong suggestions that this may 
have been the case. 

In a former conmiunication* I pointed out that Cerions could stand 
4 days of complete immersion in sea-water. This renders it probable 
that they may have been transported on driftwood. Their occurrence 
in lowland regions and their habit of affixing themselves to stumps and 
dead wood during estivation render them especially adapted for this 
method of distribution. A hurricane might flood a region occupied by 
Cerions and set adrift 100 or more on a single log, which, after floating 
for an indefinite period, might effect lodgment in a favorable habita- 
tion and thus start a new colony. If this is the chief method for long- 
distance progression, we would have to look to our ocean currents as 
the determining factor of the direction of Cerion movement. This, of 

*Year Book No. 11, Carnegie Institution of Washington, 1912, p. 131. 



54 EXPERIMENTS IN THE BREEDING OF CERIONS. 

course, points to a northward movement, and I would not be at all sur- 
prised, therefore, if fossil ancestors were found in South America, and 
even fossil members in the chain of the Windward and Leeward Islands. 
The elements of this chain have at various times been subjected to sub- 
sidence which may have eliminated the living members. If South 
America is also the cradle of the Cerions, then the first migration must 
have taken place at an exceedingly early period — at all events, prior to 
OUgocene times, for at that period we find them well established in the 
silex beds at Tampa, Florida. 

The Bahama Cerions offer an interesting field for speculation. 
Here we find to-day thousands of colonies, sometimes occupying slight 
elevations separated by slight depressions occupied by shallow water. 
It appears now that these colonies are perfectly good species. 

Our experiments on Newfound Harbor Key indicate an unusual 
fertility on the part of the cross between Cerion viaregis and Cerion 
incanum, and one wonders if such a crossing, where fertile offspring 
are produced, may not have a rejuvenating effect upon such a hybrid. 
As stated before, w^herever I have noted a state of flux among mollusks, 
whether land, fresh-water, or marine, it was found that with this condi- 
tion there was always associated a very large production of individuals. 
This is true to such an extent that the fluxed element has always been 
the dominant form of the group to which it belongs in the region 
occupied by it. This would suggest that crossing has an energizing 
effect which seems to enable the new product to surpass its associated 
congeneric forms in the production of offspring. 

It seems possible that during the glacial period, when the low state of 
water in the sea united the numerous keys which constitute the Bahama 
Archipelago into one land mass, forms separated by sea barriers during 
Pliocene times were enabled to come together and to cross. It is not 
at all improbable that this crossing may have resulted in an efflores- 
cence of new forms which may have swarmed over all the shores where 
we now find the Cerion glans group and probably other groups repre- 
sented. The close of the glacial period, returning the water to the sea, 
again split up the region into numerous islands and promontories where 
the ancestors of the Cerions of to-day were stranded in colonies and 
where inbreeding gradually eliminated diverse characters, eventually 
resulting in the more or less homogeneous expression which we now 
find in each colony. 



EXPLANATION OF PLATES. 



Plate 1. Cerion incanum (Binney). 

Plate 2. Cerion casablancoe Bartsch. 

Plate 3. Cerion uva (Linnaeus). 

Plate 4. Cerion crassilabris ("Shuttleworth" Sowerby). 

Plate 5. Cerion viaregis Bartsch. 

Fig. 1, plates 1-5. Central nervous system, posterior aspect. 



a. g. Abdominal ganglion. 

a. n. Abdominal nerve. 

b. c. Buccal commissure. 

b. g. Right buccal ganglion. 

b. V. Blood-vessel. 

c. b. c. Left cerebro-buccal commissure. 
c. g. Right cerebral ganglion. 

c. m. Cerebral commissure. 

c. pe. c. Right cerebro-pedal commissure. 

c. pi. c. Right cerebro-pleural commissure. 



c. r. n. Right cephalic retractor nerve . 

1. pi. g. Left pleural ganglion. 

m. n. Mantle nerves. 

o. n. Right optic nerve. 

pe. g. Pedal ganglion. 

pi. pe. 0. Left pleural pedal commissure. 

r. pi. g. Right pleural ganglion. 

r. u. pi. g. Right upper pleural ganglion. 

8. n. Right sensory nerve. 

t. n. Right tentacular nerve. 



Pallial organs from ventral side. 

p. V, 



Pulmonary vein. 

Ureter. 

Ventricle. 



Fig. 2, plates 1-5. 

a. Auricle. 

i. Intestine, 

k. Kidney. 

Fig. 3, plates 1-5. Anterior termination of buccal retractor muscle. 

1. Left branch. r, r. 

r. Right branch. 

Fig. 4, plates 1-5. Genital system, from dorsal side. 



a. Atrium. 

a. g. Albumen gland. 

f. Flagellum. 

h. d. Hermaphroditic duct. 

h. g. Hermaphroditic gland. 

o. r. Ocular retractor. 

ov. d. Oviduct. 



p- 




r. 


m. 


8. 


P- 


sp 


.. d. 


V. 




V. 


d. 


V. 


r. 



Fig. 5, plates 1-5. 
Fig. 6, plates 1-5. 



Jaw. 
Radula. 



Rachidian tooth. 
1st lateral tooth. 
4th lateral tooth. 
6th lateral tooth. 
7th lateral tooth. 



10. 
12. 
13. 
16. 

18. 



Radular retractor. 



Penis. 

Penis retractor muscle. 

Spermatheca. 

Spermatic duct. 

Vagina. 

Vas deferens. 

Vaginal retractor. 



10th marginal tooth. 
12th marginal tooth. 
13th marginal tooth. 
16th marginal tooth. 
18th marginal tooth. 



Plate 6. Cerion incanum (Binney) and Cerion viaregis Bartsch. 

Fig. 1. Alimentary tract of Cerion mcanwrn from dorsal side. 

Fig. 2. Musculature of Cerion incanum, uncoiled. 

Fig. 3. Atrium of Cerion incanum, opened to show fleshy protuberance and fleshy ribs. 

Fig. 4. Side view of central nervous system of Cerion viaregis. 

Ocular retractors. 
Penis. 

Right pleuro-pedal commissure. 
Right pedal nerves. 
Right cephaUc retractor. 
Right pedal ganglion. 
Right pleural ganglion. 
Salivary ducts. 
Salivary gland. 
Right sensory nerve. 
Stomach. 

Right tentacular nerve. 
Tentacular retractors. 
Vaginal retractor. 
pi. g. Upper right pleural ganglion. 
Vagina. 



a. 


Anus. 


0. r. 


ar. 


Esophageal nerve ring. 


P- 


b. d. 


Bile ducts. 


pi. pe. c. 


b.g. 


Right buccal ganglion. 


p. n. 


b. m. 


Buccal mass. 


r. c. r. 


b. r. 


Buccal retractor muscle. 


r. pe. g. 


c. 


Columellar muscle. 


r. pi. g. 


c. b. c. 


Right cerebro-buccal commissure. 


s.d. 


c. g. 


Right cerebral ganglion. 


8. g. 


c. pe. c. 


Right cerebro-pedal commissure. 


8. n. 


c. pi. c. 


Right cerebro pleural commissure. 


St. 


int. 


Intestine. 


t. n. 


1. c. r. 


Left cephalic retractor. 


t. r. 


1. pi. g. 


Left pleural ganglion. 


V. r. 


m. 


Mouth. 


u. r. pi. g 


m. n. 


Mantle nerves. 


v. 


oe. 


Esophagus. 





65 



BARTSCH 



PLATE 1 




V 



•if h.c' h.g. \' 



jji.pe.c. 



c.pe.c. 
r.pl.e. 



iMi.ji/.y. 



r.ld.rj. 



"•■"■•fr 'iU 






r 



;.,>(.!/. 




;•- (. 



,^ 



1 

r — 



h.d. . 


■ /7 




1. - / 



/..(/. 



C-c^>^ 



/..A .i 



, ap.d. 




HELIOTYPE CO. BOSTON 



Cerion incanum (Binney). 



PLATE 2 




HELIOTYPE CO. BOSTON 



Ceriou casablancae Bartsch 



BARTSCH 



PLATE 3 



\k '■•'»• 



\7'/-;;: 



;»!.j»c.c. . 





---// 





HEtlOTYPE CO. BOSTON 



Cerion uva (Linnaeus). 



PLATE 4 



^ 




/.,./.(/ 



P ■"• », 








o.r. 

HELIOTYPE CO. BOSTON 



Cerion ciassilabris ( "SliuttleworlJi " Sowejby). 



BARTSCH 



PLATE 5 





3 



4 - r.r. 





\ i 




HEIIOTYPE CO. BOSTON 



Cerion viaregis Baitscli. 



BARTSCH 



PLATE 6 



_ - u.r. ,' ((. 




r-e.r.--^- 




\\ 



"V", -■/'*'■''"' 



i- h.r. 



<?fca: 



% 




•■■'^^^ 



l.pUg. 



HELIOTYPE CO. BOSTON 



C'erion incammi (Hiiincy) and CfMioii viaregis Hartscli. 




^^ 



7 



13 



x^ 



19 



W 



25 



31 

Ficis, 



r •■ 



.t 



"i^ 









\0 

14 



26 






^1 






15 






21 



\# 



27 



V 



10 



16 



22 



28 




5 






17 



\# "^0 



23 

'A 

29 




6 
12 



-«# 



18 



24 




32 33 34 35 36 

1-3G. Check series of Cerioti narcgis. No. 21 tj'pe of Ccrion viarcgis. 



BARTSCH 



\0 



M 



43 



1^ 



49 



'# 



55 




'# 



61 



^t^'. 

■5^':' 



67 



m\ 




m 

38 







44 



.' i 



1 



50 



/:V 



56 




62 




^ v;^ 



39 




45 









51 



H« 



57 




63 





40 




m 



46 



'^V 



52 



58 




64 





41 








47 



53 



•<■ '^«> 



59 



^, 



65 




68 69 70 71 

Figs. 37-72. Check series of Cerio7i viaregis. 



m 

42 



48 



X< 



54 




60 




66 




72 



BARTSCH 





75 



76 




^■ 



78 









79 




X# 



81 



82 




83 




i^ 



84 




85 





97 




86 




92 




87 



>if 



93 




tip 



94 




jir-,. 



.%^, 



89 



95 



98 99 

Figs. 73-100. Check series of Ccrion viarcgis. 



%0 



90 




100 



PLATE 10 



w 




h 

w 



13 









14 



20 




26 



i 






15 




21 



27 





10 




f 






22 



t 



28 




^*•^ 




it 




17 




23 




29 






18 




24 




36 



32 33 34 35 

First generation of Florida-grown Ccrion viaregis from the Second Ragged 
Key north of Sands Key. 



BARTSCH 






^ 


if'' 


i^ 


''4 


^ 


3? 


38 





67 








tM 





56 57 





^ 



PLATE 11 



40 




46 



52 




70 





59 







72 



73 74 75 76 

Figs. 37-76. First generation of Florida-grown Ccrion I'iaregis from the Second Ragged 

Key north of Sands Kc\'. 



<i 




II 



PLATE 12 




A^,. 




^ll 




13 




19 



25 




31 

Figs. 1-36. 



.\ 



14 



20 
26 




32 



^,.^ 



# <• 



9 




15 



m 



V 



21 



"'*;. 



11 



% 



33 




10 



16 



22 
28 

I 



34 




T«»y ^#/ 



17 



23 




29 




35 







30 



<P 



36 



First ficnoration of Florida-srowii Ctrion viarcgis from Boca Cirandc Key 



BARTSCH 



PLATE 13 




37 




43 



\< 



49 









50 





62 




39 







51 






57 



fi 



63 



W <4 




■nil 



9J 



46 




52 







47 



53 



^$M 



r#' 



58 


59 


S 


^ 


64 


65 




42 
48 



54 



^ 



60 





72 



67 68 69 70 . 71 

Figs. 37-72. First generation of Florida-grown Cerion vian-gis from Boca Grande Key 




73 





85 



^^tr 



91 




103 




PLATE 14 




80 




86 







81 





^ 'i0' ^4 



76 





94 




98 


99 


100 


/>v 






/, ;,\ 


^.x. 


ra, 




' ■» 


.^ 






83 





95 



^4 



101 



^0 



104 105 106 107 

Figs. 73-107. First generation of Florida-grown Ccri 




78 




84 




90 





102 



-groun C cnon viarcgia from Boca Grande Key. 










^ 




i 

10 



■% 

11 



12 




19 



% 



14 



20 



15 



21 



16 



\ 




s L 111 




3 






J 



22 






17 



23 






18 



24 



25 



# 



31 



4 



26 



32 



i 



27 



i 

33 



28 

i 

34 



I 



29 



35 




30 



\ 



I 



36 



Fjgs. 1-36. First generation of Florida-grown Cerion viarcgis from Colony E on 

Loggerhead Key. 



BARTSCH 



37 

% 

43 



38 



44 



39 






45 




46 



41 



PLATE 16 




42 



47 



49 



50 



\V 



51 



i'0 

52 




54 



55 



.v!5 



56 



57 






58 



59 



m 



60 



61 



4 



62 



63 



64 



65 



66 



67 



i 



68 






69 70 71 72 

Fics. 37-72. First generation of Florida-grown Ccrion liarecjis from Colony E on 

Loggerhead Kev. 



BARTSCH 



PLATE 17 



73 



4 



74 



75 



76 




77 



78 



79 



I 



80 



h 



81 



82 



83 



m 

84 



85 



i§ *i^ 



86 



87 






89 



90 



€ 



91 



92 




93 



94 






95 



96 



97 




103 



98 




104 



99 



100 



105 



106 



101 




102 



107 108 

Figs. 73-108. First generation of Florida-grown Cerion riaregis from Colony E on 

Loggerhead Key. 



BARTSCH 



109 



110 



T J, 




111 



^\ 



112 




113 



PLATE 18 

114 




115 



121 





W 


m 


W 


116 


117 



122 



^ 



m 

123 



118 



124 






m '^' 



i 



125 



120 



126 



127 




133 



I 



139 



m 



128 



134 



140 



129 




135 







130 



136 





131 



1 



w 



137 




132 



138 



141 142 143 144 

I'iGS. 109-144. First Kencration of Floridii-jrrown Ccrwn riarcgi.-. from Colony K on 

I.o;?g('rl)cad Key. 



BARTSCH 




145 



146 



■A ' 



151 



152 



147 



153 



148 



154 



149 



4: 



155 



150 



156 



""E. 



157 



158 







159 



160 



i 

161 



162 



m 

163 



164 



165 



W 



166 



167 




168 






169 



170 



% 



171 






172 



4] 



1 

173 



4 



174 



€ 



175 



176 



m 



177 




ij ii 



178 



179 



180 



Figs. 145-180. First generation of Florida-grown Cerion viarcgis from Colony E on 

Foggerhead Key. 



BARTSCH 



J 



181 



187 



# 



182 



183 



188 



189 




m 

184 185 



190 



191 



PLATE 20 

186 




192 



193 




194 



195 



196. 



197 



198 



199 



I 



205 



211 

FIU.S. ISl 






200 



206 

/ 






^4 



201 



207 



202 



208 



9J 



203 



»M 



209 



^: 



204 




210 




212 213 214 215 

-2113. Fir.st^generation of Florida-grown Cerion viaregis from Colony E on 
Loggerhead Key. 



217 




223 




229 



218 



230 




219 




225 



231 




220 




226 



<t 



232 




227 



233 




222 



228 



234 



4 

235 




'M it 



237 



238 



239 



1? 

9 



240 



1 

241 






242 



243 




^ 



244 




246 



245 

I 



247 248 249 250 

Figs. 217-250. First generation of Florida-grown Ccrion vian-gis from Colony E on 

Loggerhead Key. 



BARTSCH 



iitf iii 











10 11 



12 



13 14 




.- *'>^ 



^ ^ 



15 16 17 18 





19 20 




21 




22 



*« 




m. 



23 24 



25 



26 





27 28 






29 30 



^. 







^ 



31 32 33 34 



1^ 






.•-.MjKtHk 




is 




35 




3.6 37 38 39 40 41 42 

Figs. 1-42. First generation of Florida-grown Cerion viaregis from Colonj' F on 

Loggerhead Key. 



BARTSCH 



"^ "^W 



43 44 45 46 








50 




57 



,\ 



51 52 









64 65 




71 72 




58 59 




53 




60 

/'a 






# ^ ^- \# 

54 



55 




^ 



61 



66 



73 



4 ^ 




m 



56 



62 63 



W ^ # \g It '^# 



67 68 G9 70 



74 75 76 77 



H0 ^ m ^m^ 



78 79 80 81 82 83 84 

Fk!S. 43-81. First generation of Florida-grown Ccrio/i riarcgis from Colony F on 
Loggerhead Kej'. 



PLATE 24 




85 



^ 



92 







;^ 



m "^^ 



r-^ 




87 






89 





90 




96 

















73 




W 



*% 






^1 



or- ' 



\W/ 



74 75 76 J J 78 

Figs. 85-100 at the top of plate. First generation of Florida-grown Cerion riaregU from 

Colony F in Loggerhead Key. 
Figs. 1-8 of the middle series. Second generation of Florida-grown Cerio7i viaregis 

from the Second Ragged Key nortli of Sands Key. 
Figs. 73-78 of the bottom series. First generation of Florida-grown Cerion viaregis 
from Colony G on Loggerhead Key. 



30 



i\ » u 



/A 



i 



9> 



•1 



I 



? 



16 



23 






13 



i 



37 



40 



42 



43 



44 



'\ 



45 



f) 

47 



49 



Figs. 1-49. First generation oC Florida-grown Ccrion I'iaregis from Colon\- G on 
Loggerhead Key. 1915. 




'■^. 




31 



K^\ 



^^^ 




14 



^C 




26 






32 








15 




YU 



33 



?V"' ,. 



4 



10 



16 



28 




*?i 



34 



»"■» 



\> 




35 




12 




^ t'/^. 



30 



■4 



36 



Fics. 1-3G. First generation of Florida-grown Ctrio)!, riciregifi from Colony (i on 
Loggerhead Key. 19 Hi. 



m 



49 



55 



38 



44 



56 



39 



45 






51 



'4 

40 



1^ 

46 



n 



'10 

52 



m 

58 



41 



/ #^ 



^T- 



47 




53 



M" ^^ 



42 



48 



<f0 

54 




*? 

i^ 



# 



60 



^ 



61 



•rr' 



67 



'\i 



62 



t 



68 



63 




f * 



64 



69 



r^ 



72 



70 71 

Figs. 37-72. First generation of Florida-grown Cerion viarcgis from Colony G on 
Loggerhead Kc3\ 191 G. 



BARTSCH 







ll # 



10 




\4 ^4 ^S 



/.\ 




^ ^ 



25 



33 



i^-^*?v^ 



26 



27 



/^mk 



34 35 




12 




13 



14 





20 21 




30 



$ ^^ ^ ■<# ^ ^ 

il « 43 44 45 ^g 






15 



16 




22 23 



"Ml ># 



31 




^ 



40 



/^v. 



¥ 



46 47 



48 






(# <# %# ^f^ N^ x# # 

49 50 51 52 53 54 55 




56 



Figs. 1-56. t'econd goiipnition of Floricla-srown Ctrion viarcgis from Colonj- K on 

Loggerhead Key. 



BARTSCH 



PLATE 29 



tl^-^*^^■■^ 







*# 



« ■ \ *' 



59 



60 



61 



62 



^ '^ '^ 



69 




74 









84 




90 




85 




91 













95 9G 97 98 ^9 

Figs. 57-100. Second generation of Florida-grown Cerion viaregis from Colony K on 

Loggerhead Kej'. 




17 








10 








'« 




% 



11 



12 



13 



19 



20 



21 




27 





# 



34 






f # ^' 



14 



* # # 

22 



29 




' « 





15 




■# \4j 





PLATE 30 



t# 






m 



16 



24 






46 47 48 49 50 .51 

Figs. 1-52. Second generation of Florida-grown Cerion riamjis from Colony M on 

Loggerhead Key. 



BARTSCH 



PLATE 31 



53 



61 



69 



/^. 



l# «* 



77 



85 




/A 







t# ^ 1C# 



58 




66 




74 




m^^ 

^^^^r 



82 




I* 



90 



59 




75 




83 






60 




,^: 



\ 



4 4 



76 



\ 
i-*'^ 



84 




93 94 95 96 97 98 99 '^ 

Figs. 53-100. Second generation of Florida-sro\yn Ccrion riarcgis from Colony M on 

Loggerhead Key. 



PLATE 32 








iiis^ 





I 



vr \ 






^# 






27 



'::^ 
<# 



33 








17 



23 



29 






34 



35 






30 



-<4 



36 



Figs. 1-36. Check series of Ctrion casablanar. No. 13 tj-pe of Cerion Casablanca:. 



BARTSCH 



l\ ^.J 








\ft 



39 



Iff V ' 



r 



40 





61 



67 



4 \f0 



44 







45 



46 



r - 



\4 



50 


51 


52 


53 






'T 


# 


'4 


H# 


V# 


<^ 


56 


57 


58 


59 



63 



P: 




64 




68 69 70 71 

Figs. 37-72. Check series of Ctrion caaablanccv . 



48 




H 

54 




66 



N# 



72 



BARTSCH 




es 




91 



4 



97 



'"^i 



74 



4f 



t: 



90 

80 



/ 



86 




# V 



75 



81 



^1* -^# 



87 



i 



92 ^ 93 

4'' 



4 



86 




82 



94 




77 



<^ %4 



83 



* V# 



89 






90 



H# <¥ '^^ X!# 



95 



96 




^^# 



99 



<^ 



100 



Figs. 73-100. Check series of Cerion casahUmae. 













10 





16 





12 




17 





13 




18 





14 






15 




20 




1-23. First generation of Florida-grown Cerion camhlanar from 
Ragged Key north of Sands Key. 
Figs. 24 and 25. Second generation of Florida-grown Cerion camhlan.cw from the 
Fir.st Ragged Key north of Sands Key. 



BARTSCH 



PLATE 33 








13 14 










4 ^. % 






^ ^ ^ ^# 

7 4 5 6 

9 10 11 12 






4 4 4 ^4 

15 16 17 18 




21 22 23 



24 



« # 



25 26 27 28 29 30 

Fitis. 1-;J0. First generation of Florida-srown Crri.on mmhlunca: from Bahia Honda Kev 



31 






48 



,n^ 



#♦**-*■** 

i^^, 






44 





# 4 



33 34 




35 




38 39 40 41 42 





45 



46 




n4I 




49 



50 







i 



55 




^ 



36 




'fi 



47 





56 



52 53 54 

Figs. 31-56. First generation of Florida-grown Ccrion casahlancce froniBahia Honda Key. 



BARTSCH 



PLATE 38 




7 

\ 



^xm. 



% *4 'i ** •ii 



# >• 



13 






il ^i 



14 




15 



m 



10 




16 





17 





18 



^ ^ ^# "• ^ ^ 

" ,0 2i 22 23 24 



^ ^ <t <4 m 



25 26 



27 



28 



29 




30 



Figs. 1-30. Fir.st gcnonition of Florida-grown Cerion casahlaiiac from Colony 13 on 

Logscilieatl Key. 1915. 




mm t^i 



Figs. 31-60. First generation of Florida-grown Ccrion camhlanccr from Colony B on 

Loggerhead Key. 1915. 




^ '^ ^ -^^ 



67 68 




74 



'^, 



80 





69 




75 




81 



v^ 




m 

82 




83 



/■^ 



85 



86 



87 



89 




T« tf ^^ ^ t#' ^ 



90 



Figs. 61-90. First generation of Florida-sro\\ii Ccnon camhlanar from Colony B on 

Loggerhead Kev. 1915. 



it# ftf 



91 



97 






93 



92 



94 





M '^ 



98 



"<# 






99 



100 






^# 



104 



i' 



105 




^4 m 'm 

107 108 

106 








114 



HIM 



115 116 117 118 119 120 121 

Figs. 91-121. First generation of Florida-grown Cerion casablanca from Colony B on 

Loggerhead Kej', 191.5. 



BARTSCH 








y^ 




m 



'S ^ 




i) "ri 






32 33 34 35 

}6. Firfit gcncrution of Flori(la-2;rown Cerion camhiinicw from Colony B on 
Loggerhead Key. 1916. 




Figs. 37-73. First generation of Florida-grown Cerion casablancte from Colony B on 

Loggerhead Key. 1916. 



BARTSCH 



PLATE 44 




■\ 



4% 





19 




25 





f i I 





tl 



1 





15 



21 




,'l 



27 






29 






30 



^ W 




31 32 33 34 35 36 

Fics. 1-36. First seneration of Florida-grown Cerion casahlanca' from Colony C 
on Loggerhead KeJ^ 1915. 



BARTSCH 



PLATE 45 






13 







^ "Mi 




15 




19 



20 



21 




^ \0 



16 





17 






^ ^ll 



A^ 





22 



23 





25 








^1^^'^^^ 



26 



27 





28 29 30 

Fk;s. 1-30. Second generation of Florida-grown Cerion casahlancw from Colony C on 

Loggerhead Key. 



.t- M 



T# 



31 







,^'-i^ 



m 




33 



'-m 



34 



W 



I T^' 



35 



36 



t^ N# ^^ X# ^# .^11 

^^ 39 40 41 .,' 

37 "^2 



^ 



43 




44 






47 



48 



49 




# "*#■ 



50 




51 



m^ 



■^ 



4> * 

53 



52 



# 



54 



A 



# 4^ # « 



55 56 57 58 59 60 

Figs. 31-GO. Second generation of Florida-grown Cerion casahlanar from Colonj' C 

on Loggerhead Key. 




Figs. 61-100. Second generation of Florida-grown Cerion casahlanca- from Colony C 

on Loggerhead Kej-. 



PLATE 




f-'^ffl 



» 







M 





* \# 




v^ 



1? 




s 



4 



v. 



14 




15 




10 






16 






12 




18 




19 




25 




% 



20 




26 






"^►>V 



22 




23 




24 




27 



29 



30 








32 33 34 35 

P'iGS. 1-36. Check series of Cerion crassilabris. 




36 



,\^ '\' 



37 



38 



PM\\ 







39 



it: J 




40 







^^ 



41 





42 



43 



45 



46 



47 



48 






^# 





49 



51 







55 




61 




67 




56 




62 





63 




52 



53 



54 




58 




64 







59 




65 




68 69 70 71 

Figs. 37-72. Clicck series of Ccrion crassilabris. 




60 




66 




72 



BARTSCH 






73 



"^ 



74 




75 






y 



76 






77 



PLATE 50 



^fci.A 



M'''.' 



78 






« '^rf) 




79 




80 




81 




1) "« \# 




85 



86 



87 



82 



/fh. 



\0 



88 




'A 



83 






#y 




84 




89 



90 



r- 



91 



92 




93 




f 

94 



i ^!# \# 



95 



96 



'^^ \^ 




^M 



w^ 



97 98 99 100 

FiciS. 73-100. Check series ol" Ccrion crassilabris. 




.^■. 



t M 




16 



10 




17 



t|p ij^ Wj^ 






« 




5 




12 



^ 



^g^^ 



13 



19 




PLATE 51 





14 





23 




24 




25 



* 



26 







27 




28 



/f'-i"^' 




29 







30 



d 



^I^^^M 



31 




32 






33 




34 





36 





37 





38 39 40 

Figs. 1-40. First generation of Florida-grown Cerion crnstiilahris, from Colony L on 

Loggerhead Key. 



BARTSCH 



PLATE 52 




45 46 47 48 

Figs. 1-50. Check series of Cerion uva. 





49 



50 




51 




58 




65 




72 




79 



I 



86 




93 



in^ 




52 




59 

A ' ■ 

66 




73 



k 



9 

80 



87 



94 




67 




74 



4 

81 




95 



54 




61 

68 
75 



82 



89 




It 




69 




83 
90 






56 



63 






70 



76 

^ 



77 







84 




# 

91 



1' y$ 



96 



97 



98 99 



^ 




57 



t 



64 



71 




78 




85 




92 




100 



Figs. 51-100. Check series of Ccrion uva. 



BARTSCH 











13 








wi, 



14 








2J, 




21 



/" 



27 









E 

10 




i. 



^# ^i 



28 






r.\ 



17 



/ 





%.i$ v# 



/^ 



V^ A# 



12 




H# W) 



18 




% 



V 



24 



t*.. 



33 



34 



P'iGS. 1-313. Check scries of Ccrion incanum. 



37 



43 



/^ 



49 



^ - - 



i ^# 



38 



44 



50 



.#^... 



39 



>- 



45" 



• ^# \4 



51 



t,'\ 
■-■"'.: 



s4 

40 



vj, \-0 ^# ^:ii' 



46 




52 



i^x 



^* '^# 



41 




47 



^# 



53 



r ■ 



42 



K^ \ 




48 




54 



^t ^#: # v# ^#) H# 



55 



56 



57 



58 



59 



60 



/ \ 



61 



67 



62 



68 

Fl(!S 



63 



#) 



64 




69 70 

37-72. Check scries of C'crion incciuint 



< # 


^^i 


65 


66 


f- 


/^•^ 


'# 




71 


12 



BAPTSCH 





85 





74 





A 



75 



^ 



^# 



81 



87 



X|| 



93 






76 




r-N 




94 






77 




89 



m 



95 






f 



V# ^* xtl H<^ 



78 




84 




90 




v# 



96 



4 ^i 



97 98 99 

Fics. 73-100. Check series of Cerion incanum. 



00 



BARTSCH 




8 



15 



22 



y 



29 



^ 

^ 



9 



^0 
3 

^\ 

10 





''If 

11 



^i ^# ^^ ^# 



16 



18 



i / 



23 



25 








30 



31 



'# '# 






32 



;Xv^- 



/^m 



/">. 




19 



^# ^# V* ^ ^# 



PS* 



33 



sm 



^4 '• 



# '\# v# 



6 



\ 



13 




20 




26 27 



lVv. 



'<# 



ii 



\* 



14 



\$ ^ 



21 



S-a 



i 



28 



^ 



35 




36 37 38 39 40 41 42 

Figs. 1-42. Cerion incanum X Cerion viarcyia from Xcwfouiul Harbor Kej'. 





57 




71 




78 

Fu; 



44 




51 




58 





72 




45 




52 








53 



54 





60 



61 



^ % 



67 



J 4/ 



68 



74 



/•. 



^^V 



55 



62 



# ^# 



69 




56 




63 




70 




77 



« 



79 80 81 82 83 84 

43-84. Ccrion incnnuni X Ceriou riarcgi.s from Xewfouiul Harbor Key. 



BARTSCH 



%^ 



85 




99 

0S 




106 



113 





86 




93 



100 




107 



114 




87 



94 






101 






r^ 



108 



^ ^ "« i# T(i 



115 




\ wpi W' i^^^ 
^ ^^ ?# v# 





89 



95 



102 



109 



116 



96 



103 






no 



90 



« .4 y <i 



97 



104 





111 






117 



118 





91 




98 



105 



112 



119 



120 121 122 123 124 125 

Figs. 85-125. Ccrinn iNcanion X Ccrion viarcrjis from Xcwfound Harbor Key,