1895.] Zoology. 167 
ZOOLOGY. 
The Influence of changed Environment on Mollusca.— 
The experiments made by Professor Semper with specimens of snails 
in order to ascertain the causes of dwarfing have recently been repeated 
by M. H. de Varigny who arrives at somewhat different conclusions 
from those of Prof. Semper. The experiments consisted in isolating 
young individuals from the same mass of ova in vessels containing dif- 
ferent amounts of water, but placed under the same conditions of food, 
temperature and light. It was found that the size of the individual 
varies with the volume of water, and Dr. Semper’s conclusion is that 
there is present some substance, as yet unknown, was necessary to the 
growth of the snail. M. de Varigny observed that while the size does 
vary with the volume of water, the dimensions vary more with amount 
of water surface than with volume alone, and increase in size persists 
when the superfices was increased while the volume was diminished. 
M. de Varigny suggests that dwarfing is due to lack of room in which 
to move about. (Journ. del "Anatomie et de la Physiologie, 1894.) 
The genus Leptophidium.—In 1863 I established the genus 
Leptophidium for ophidiids having a slender form and regularly em- 
bricated scales. Having had occasion recently to refer to Hallowell’s 
“ Report upon the Reptilia of the North Pacific Exploring Expedition ” 
(Proc. Acad. Nat. Se. Phila., 1860) 1 found that he had used the same 
name previously for a genusof snakes. After endeavoring in vain to 
identify Dr. Hallowell’s genus, I asked Dr. Stejneger and he informed 
me that he had also vainly attempted to identify the same snake and 
that no specimens answering to Hallowell’s diagnosis were in the Na- 
tional Museum. Prof. Cope has not mentioned the name as that of a 
valid genus or as a synonym in his Catalogue of Genera of Snakes. 
(Bull. U. S. Nat. Mus., no. 32, 1887). 
But, whatever, may be ascertained to be the value of Hallowell’s 
genus, there is no doubt that Leptophidium cannot be retained as the 
name of the Ophidioid genus. Lepophidiuwm (scale, and Ophidium) 
may be given as a substitute and to recall the regular squamation 
characteristic of the genus. 
Lepophidium has proved to be one of great interest and to be repre- 
sented by a number of species in moderately deep seas. In eadivion oe 
(1) L. profundorum and (2) L. brevibarbe, the fe 
o 
