HARRIS : CRAYFISHES GENUS CAMBARUS. 103 



15. Kansas. 



1. Ward's creek, Shawnee county. (F., '856.) 



2. Stagnant ponds, Douglas county. (Harris, '00.) 



41. Tennessee. 



1. [Trib. Mississippi R.], Obion county. (P., '85.) 



Harris ('02) summarizes most of the literature on the habits 

 of this species and presents his own observations. C. immunis 

 has been reported from muddy ponds in Michigan (Faxon, '85) , 

 Minnesota (Herrick, '82), Illinois (Forbes, '76), and Indiana 

 (Hay, '96). The material he examined seemed quite variable, 

 and a part of it probably belongs to Faxon's variety spinirostris. 

 In Douglas county, Kansas, where his observations were made, 

 C. immunis is the most common species, being found in road- 

 side ditches and stagnant ponds, and is exceedingly abundant 

 in stagnant ponds in an old river-bed. These ponds are from 

 six to eighteen inches deep, depending upon the dryness of the 

 season, are very muddy, and have usually around the edges a 

 rank growth of Polygonum and plants of like habit. From such 

 a pond, one day in October, 1898, were taken about 1500 speci- 

 mens, of which only a few were less than two and one-half 

 inches in length. There were not more than a half-dozen small 

 specimens in the whole lot, but other collections were made 

 which showed the animals in all stages of development. In 

 some of the ponds C. immunis seemed to be the only species, 

 but in others it was found associated in predominating num- 

 bers with C. gracilis and C. virilis (?), but these do not occur in 

 such great numbers as does C. immunis. According to him, C. 

 immunis is a burrowing and, at least to a certain extent, a 

 chimney-building species. 



Hay's ('96) suggestion as to the perishing of the crayfish 

 upon the drying up of the ponds seems to be due to lack of op- 

 portunity for examining the ponds in different conditions, since 

 in many places which were examined, in all stages of drying up, 

 no considerable number of dead ones were found. In early 

 September, 1900, a pond which earlier in the season had con- 

 tained many crayfish was found to contain few crayfish, but had 

 many burrows around the edge. One of these, having a chim- 

 ney about four inches high and five inches in diameter at the 

 base, fifteen inches deep, and an inch and a half in diameter, 

 with a cistern-shaped chamber about three and one-half or four 



