HARRIS : CRAYFISHES GKNUS CAMBARUS. 105 



SO smooth as Schufeldt's ('97) description would seem to indi- 

 cate. Prints of the chelse in the mud were noticed. One case, 

 at least, was noticed, in which the shaft was filled with clay to 

 somewhat below the surface of the ground. ^^ The shaft usually 

 goes straight down, but in some cases may be somewhat sinuous. 

 They are quite deep, one being followed down four feet with- 

 out reaching the end. He was not able to convince himself of 

 the presence of a ledge upon which the animal could rest, as 

 stated by Hubbard (Faxon, '84 and '85), for C. argilUcola, al- 

 though in some cases the burrow seemed to be expanded in a 

 way which might serve for this purpose. 



One case was noticed in which a lateral shaft originated about 

 six inches below the surface and ended somewhat higher, about 

 eighteen inches from its connection with the main shaft. It 

 might seem that the animals do not like to stay under water 

 very long, since, when an excavation extending somewhat be- 

 low the water was made in one of the burrows, the animal two 

 or three times came out of the water and darted back before an 

 attempt to catch him was finally successful. 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. The theory that 

 the burrows are made to escape the dry months of summer seems 

 to be the correct one for this species, while, of course, the pur- 

 pose of the burrows made or enlarged upon the approach of 

 winter is evident. It is certain that they are not adopted as re- 

 treats while the eggs are being hatched, for females were taken 

 in the open ponds in the fall, apparently soon after the eggs 

 were laid, and they came out early in the spring, about March 

 20, to complete the process of hatching the eggs. 



Harris ('02) reports material from a stagnant pond on the 

 prairie, near Onaga, Pottawatomie county, Kansas. The ponds 

 had been in existence about six years and had never been known 

 to go dry. They probably had no connection during high water 

 with the nearest creek, which was about a quarter of a mile 

 away. No fish had ever been found in the ponds, but specimens 

 of Ambly stoma tigrimim Green, which is sometimes found in the 

 same localities as C. immunis in Douglas county, were found. 



17. I have since found numbers of burrows of this or other species in which this is the case, 

 clay of a very different nature from that of the chimney, and apparently coming from a different 

 stratum, being used. 



