No. 411.] CAMBARUS IMMUNIS HAGEN. IQI 
cases may be somewhat sinuous. They are quite deep, one 
being followed down for four feet without reaching the end. 
I am not able to convince myself that there was a ledge 
upon which the animal could rest, as stated by Hubbard? for 
C. argillicola, although in some cases the burrow seemed to be 
expanded in a way which might serve for this purpose. In 
one case examined quite early in the fall, the main shaft went 
straight down ; at a distance of about six inches from the sur- 
face a branch went off at almost right angles and ended 
somewhat higher than it originated about eighteen inches from 
its connection with the main shaft. It might seem that the 
animals do not like to stay down in the bottom of the burrow 
very long, at least early in the fall, since when a small exca- 
vation extending somewhat below the water mark was made in 
one of the burrows the animal came to the top and darted 
back two or three times when I attempted to catch him, which 
I finally succeeded in doing. The burrow was left for a few 
minutes and when again examined a medium-sized female had 
crawled out of the water and was standing on the almost 
perpendicular side of the excavation. 
Hay's? theory, that the burrows of C. diogenes are made to 
escape the dry months of summer, seems undoubtedly the 
explanation for the summer burrowing of this species, while 
of course the purpose of burrows made or enlarged upon the 
approach of winter is evident. It is certain that the burrows 
are not adopted as retreats, while the eggs are being hatched, 
for I have taken the females in the open ponds in the fall, 
apparently soon after the eggs were laid, and they come out 
early in the spring — about March 20 —to complete the 
process of hatching the eggs. 
UNIVERSITY OF KANSAS, 
Nov. 10, 1900. 
1 Faxon, Walter. je aep of New —— of Cambarus, Proc. Am. Acad. 
Arts and Sci., vol. xx (1884), p. ? Hay, W. P. cit. 
