100 KANSAS UNIVERSITY SCIENCE BULLETIN. 



of the numbers of red crayfish seen after a heavy, washing rain, 

 and was inclined to consider the species widely distributed. 



He considers that individuals of this species must exuviate 

 in their burrows, since the ponds in which the females are found 

 in the early spring were very carefully watched without finding 

 a specimen which was at all soft from exuviation. In the spring 

 females were occasionally found in these ponds with a few young 

 which were nearly old enough to leave the parent. This makes 

 it seem altogether probable that those females without young 

 liave lost them before or immediately upon taking to the open 

 water. In C. immunis, the females exuviate in the spring as 

 soon as the young abandon them, but this would seem to indi- 

 cate that such is not the case with C. gracilis. 



In the fall of 1900 there were many young crayfishes which 

 seemed to be C. gracilis in the ponds, about October 20 to No- 

 vember 20 appearing in great numbers about the same time 

 that C. immunis disappears. Young of this species were also 

 noticed early in the spring of 1900. These young crayfish, which 

 were from three-fourths to seven-eighths of an inch in length 

 when they disappeared in November, 1900, appeared again about 

 the 1st of March, 1901. They were taken in great numbers. 

 A few days later the ponds froze over, but the animals were still 

 to be found, apparently as plentiful as ever, under a layer of ice 

 about an inch thick. They grew rapidly, and by the 1st of May 

 had attained a length of from one to nearly one and one-half 

 inches. 



Many smaller animals of five-eighths of an inch in length 

 were found in the ponds and ditches on May 9, probably the 

 young of C. gracilis, which were still carried by the females as 

 late as March 27. In the spring of 1901 the adults did not ap- 

 pear until after the young. 



He did not succeed in determining the date of copulation or 

 laying of eggs. The eggs in the ovaries of females taken in this 

 way were by no means fully developed. 



This species, as compared with some others, C. Immunis for 

 instance, he considers shows a very small percentage of mutila- 

 tion, it being very seldom that an individual is found with one of 

 the great claws wanting, or showing any indications of having 

 been regenerated. 



Harris ('02) records the finding of an adult female in a stag- 



