52 General Notes. [ January, 
The first and second generations were each smaller than the 
parent stock, and this last, a third generation, had a shell only 
about four-sevenths as long as measured by the figures. 
The animals of Lymnza are perfect hermaphrodites, combining 
in each individual both male aud female organs, therefore it is 
not likely that the a oral ancestor of Mr. Whitfield’s group was 
a deficient specimen. rtheless, besides the diminished size 
and spire, Mr. Whitfield ‘Wound that the male organs had disap- 
peared and the liver become considerably reduced in size. A 
dicecious species had, therefore, in all probability become a monce- 
cious one on account of its removal to the aquarium. 
This paper reminds us very strongly of the researches of Carl 
Semper upon Lymneza, in which he shows that the supply of 
food and other things being equalized in a number of aquaria, 
that the size of the shells depends upon the temperature. w 
temperature onog inimical to the development of the largest size 
in any specie 
In this case Me Whitfield, who is a palæontologist well known 
to workers in his own field, did not undertake his researches with 
the idea of conducting an experiment, but has, nevertheless, 
brought out a very similar series of modifications. Curiously | 
enough, however, he took a species which reaches a very large size 
in northern waters, a  rodacp it to the almost tropical cli- 
mate of a home aqua 
Mr. Whitfield has caly been very fortunate in leading the 
way into this field o oe in experimental zoology with so 
suggestive a paper.—A. 
INFLUENCE OF BOTS ON e — The influence of some — 
of the principal poisons on crustacea has lately been experimented 
oy M. Yung. The animals treated were the crab and lobster. _ 
It was found that curare acts on these animals in the same way _ 
as on vertebrates, but with much less power; it produces difficulty 
eee, A ee oe S 
ee a cee | eee AA E EEA 
s movements, The action of nico- 
lent for crustacea as for vertebrate 
DIFFERENCE IN THE HABITS OF SCALOPS AQUATICUS AND SCA- 
PANUS AMERICANUS. —A valued correspondent, Mr. Elisha Slade 
of Somerset, Mass., finds decided differences in the habits of the 
1 For this latter name see AMERICAN NATURALIST, XIII, 1879, p, 189. 
