A\ HERMAPHRODITIC CRAYFISH 271 



AN HERMAPHRODITIC CRAYFISH OF THE SPECIES 

 CAMBARUS (FAXONIUS) OBSCURUS BAGEN. 



I. L. RESSLER. 



Recently, in the course of my work in the laboratory, an 

 abnormally developed crayfish was brouglH to my attention. 

 This animal had present both male and female characters. 

 The length of this apparent hermaphorite is 77mm., some- 

 what smaller than the average for this group. 



There is a great variation in the general appearance as com- 

 pared to the normal creature. It has the characteristic broad 

 abdomen of the female. The fifth pereipod alone shows no 

 variation, containing the genital opening in the coxopodite as 

 found in the normal male. The third pereipod has no genital 

 opening. This would seemingly make it a male appendage 

 were it not for the fact that the clasper is not present on 

 the ischiopodite. Between the coxopodites of the fourth pair 

 of pereipods is found the annulus ventralis, common only to 

 females. The first pleopods are characteristic of the male. 

 They are, however, somewhat shorter and stouter than the 

 normal first pleopods, and extend cephalad only as far as the 

 anterior side of the fifth pereipods. The second pleopods are 

 essentially male structures, although not so prominent. (See 

 figure 42, A and B. 



The above description shows that the specimen bears, ex- 

 eternally, markings characteristic of both the male and female. 

 The internal organs of reproduction are equally interesting. 

 The sperm duct arises apparently from a pair of very small 

 ovaries which are situated in a position corresponding to that 

 of the anterior lobes of the testes. The sperm duct itself is 

 normal in every respect and opens to the exterior through the 

 coxopodite of the fifth pereipod. The posterior lobe of the 

 testes is present, extending as far caudad as the first abdominal 

 segment, between the lobes of the liver. 



There are several cases on record where hermaphroditism 

 has been described. One of the above species has been de- 



