ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
55 
by the addition of faecal matter. The faecal matter obtained from cases 
of typhoid was more inimical than that obtained from healthy subjects. 
Y. As to the infection of the oyster by the micro-organisms, it was 
found that when oysters were laid down in the open water of the bay 
the colonies present were especially small in number, while those laid 
down in proximity to a drain pipe had an enormous number of colonies. 
In the case of oysters grown in water infected with the bacillus of 
typhoid, it was found that they could be identified in cultures taken 
from the water of the pallial cavity and rectum 14 days after infection. 
As it was found that the typhoid bacillus will not flourish in clean sea- 
water it is possible that, if oysters are carefully subjected to a natural 
process of cleaning, they may be freed from contamination without 
spoiling the oyster for the market. 
New Lamellibranch Commensal with an Echinoderm.* — M. F. 
Bernard finds among the collections from Cape Horn two examples of 
Tripylus excavatus , which, instead of carrying young in the depressed 
ambulacra, bore therein a small Lamellibranch not more than 3 mm. 
long. The author gives some details as to the character of the shell, 
which appears to be of an embryonic type, while the internal organism 
shows considerable specialisation. The abductor muscles are greatly 
reduced, the foot is poorly developed, there is no byssus. The digestive 
tube is very simple, stomach large. The liver occupies the two anterior 
thirds of the visceral mass. The kidneys are greatly reduced. The 
gonad is hermaphrodite, and occupies the hinder third of the visceral 
mass. The most interesting organs are the gills. On each side there 
is a single branchial plate, so arranged as to form a hinder pallial cavity, 
which only communicates with the anterior by a median orifice. This 
hinder cavity is utilised as an incubatory chamber. The author proposes 
to call this lamellibranch, Scioberetia australis , and promises to discuss 
its affinities on a later occasion. 
Arthropoda. 
a. Insecta. 
Seasonal Dimorphism of Butterflies.f — Prof. A. Weismann has 
during the last ten years made a number of new experiments on the 
seasonal dimorphism of butterflies, which was the subject of one of his 
earlier studies in evolution (1875). His object has been to discover 
how far the phenomenon of seasonal dimorphism may be directly induced 
by the influence of altered temperature, and how far differences of climate 
may be credited with producing permanent, i. e. transmissible effects on 
colouring. 
He first describes experiments and observations on CTirysophanus 
phlaeas L., some of which, of Italian origin, were reared in Naples and 
others at Freiburg, while others again, of German origin, were reared at 
different temperatures. The first question asked was, whether the tem- 
perature which acts on the pupa affects the colour of the butterfly, and 
the answer is decisively in the affirmative. The second question was, 
whether the result of the influence of temperature becomes inherited ; 
* Comptes Rendus, cxxi. (1895) pp. 5G9-71. 
f Zool. Jahrb. Abtli. Syst. Biol., viii. (1895) pp. 611-84. 
