AX HERMAPHRODITIC CRAYFISH 273 



A specimen of Cambarus rusticus is described as follows: 

 '"The specimen is externally a female, possessing the female 

 type of claws, a well developed annul us. female sexual open- 

 ings, and no hooks on the third pereipods. But the first pleo- 

 pods are peculiar; they are short and stout; the bases are 

 identical with those of the male pleopods ; the distal parts, 

 however, reach only to about the middle of the coxopodilrs 

 of the fourth pereipods; their tips are soft, blunt and slightly 

 curved inward, and possess the furrow which divides them 

 into an inner and an outer part, but these parts are not sepa- 

 rated at the tips. The second pleopods are of the female type. 

 The specimen is apparently a normal female only the first 

 pleopods are transformed in a peculiar way, resembling the 

 male type generally, but differing from the specific shape." 



Zoological Laboratories, 

 Iowa State College. 



»Ortmann : The Crayfishes of the State of Pennsylvania. 



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