i_ &«^
*^ /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,
