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THE AMERICAN NATURALIST [Vol. XLIII 



first somite of the abdomen, while those on the second are 

 like the following ones. But the limbs on the first somite 

 of the abdomen of the male are quite remarkable conduits 

 that conduct the sperm ; and the limbs of the second 

 somite are peculiarly adapted to fit against the first as a 

 necessary part of this sperm-transferring apparatus. 

 The limbs of the thorax may also be modified so that 

 some of them bear hooks for holding the female. 



In the case of Cambarus the female sperm-receptacle 

 is a unique median pocket in the shell, which is of as much 

 physiological necessity for the race as are the ovary, the 

 testis and the male appendages that transfer the sperm. 



The gynandromorphic crayfish to be described was a 

 small sized and probably immature male of the species 

 Cambarus affinis, taken in a lake at East Hampton, Conn., 

 by Mr. Kenneth X. Atkins. 1 



The external appearance of this specimen was that of 

 a male 55 mm. long with small chela? only 30 mm. long, 

 having the hand 15 mm. long and 5 mm. deep. The 

 antennae were 45 mm. long. The papilla? of the fifth or 

 ultimate legs seemed normal. The second abdominal limbs 

 were as usual in a male but the first were of the puerile 

 or so-called second form of male limb very like that 

 found in a young normal male five months old and 38 

 mm. long. The tips were blunt and there was a free 

 joint above the basal joint. The attaching hooks of the 

 third, or antepenultimate, legs were short and blunt, but 

 normal for the young male. There were the usual long 

 male hairs on the spine between the ultimate legs, and 



upon the geographical distribution of crayfishes. New England being 

 singular in the fewness of its crayfishes, which are largely restricted to the 

 drainage into the St. Lawrence, the question to be settled is whether the 

 crayfishes are absent because they never got there or because some character- 

 istics of climate, soil or biological environment are inimical to them. It 



ago, being, it is thought, brought there by fishermen. Since these crayfish 

 are fairly abundant there now this is evidence that crayfish can live in 

 this region, and favorable to the idea that the relative absence of cray- 

 fishes throughout these states is due to their not having migrated in there. 



