124 
Miscellaneous . 
Variations in Bulimus exilis. 
Dr. Benjamin Sharp called attention to two varieties of Bulimus 
exilis which he had found on the islands of Guadeloupe and Dominica. 
One variety was characterized by broad dark brown bands which 
run parallel with the coil of the shell, while the other was peculiar 
in possessing small and very faint bands, which in many speci- 
mens were entirely absent. The banded variety was found to be 
common in Guadeloupe, while the bandless one was rare. In 
Dominica, which is separated from Guadeloupe by a channel of only 
twenty-three miles, the banded variety was very rare, while the 
light or bandless one was comparatively common, although indi- 
viduals were by no means so common in Dominica as in Guadeloupe. 
He spoke of the probable cause of the variation, and suggested that 
it was due to some environmental action. The island of Dominica 
being wholly of volcanic origin would produce a different kind of 
food from the Grande Terre portion of Guadeloupe, which in forma- 
tion is purely coral. It was on this portion of Guadeloupe that the 
specimens of B . exilis were collected. It is known that Dominica 
has many species and some genera of plants that are peculiar to the 
island, and this difference of food may in some way account for the 
differences in this species of land-snail. Dr. Sharp said that it is 
probable that the dearth of land-shells on the volcanic islands and 
their comparative plenty on the coral and continental islands of the 
Caribbean group is due to the absence of carbonate of lime in the 
former and its presence in the latter. 
Remarks on the Exuvice of Snakes, 
Dr. Benjamin Sharp further spoke on the exuviae of two snakes, 
which were shed in the laboratory of the Academy two days pre- 
viously. These snakes, Eutanceia sirtalis , B. & G., had been pre- 
sented to the Academy on the 19th of March, 1890, and had been 
captured the day before in New Jersey. The whole process of 
shedding the skin had been observed. One of the snakes was in the 
water when first seen, and, coming out upon the sod, it shrugged 
and shook itself for a moment ; then, getting between the glass of 
the vivarium and the box containing the earth, the skin parted at 
the jaws and the animal crawled out, leaving the exuvia. The 
cerebral portion being fixed, the animal passed through the opening, 
so that the discarded skin, as is always the case, was turned wrong 
side out. One of the specimens was interesting as it was entirely 
perfect, without the slightest rent and not a scale missing. The 
other was perfect, but there was a considerable rent on each side of 
the jaw. The operation took less than one minute. The snake was 
startled about the middle of the process. It crawled away from the 
exuvia very rapidly.— Proc. Acad, Nat. Sci. Philad April 15, 1890, 
pp. 148 and 149. 
