Vol. XVII September, 1909. No. 4. 



BIOLOGICAL BULLETIN 



SPERM-TRANSFER ORGANS IN CAMBAROIDES. 



E. A. ANDREWS. 



Amongst the arthropods it is not uncommon for some of the 

 limbs to be used for transferring the sperm from the male to the 

 female. In some of these cases the path of the sperm from the 

 male to the egg is very complex, and we may speak of " indirect 

 sperm-transfer." 



Thus in the common crayfishes of the United States, of the 

 genus Cambarns, the first and the second limbs of the abdomen 

 of the male are special organs that we will call the first and the 

 second stylets, which conduct the sperm from the male openings 

 upon the bases of the fifth pair of walking legs to the surface of 

 the female. In the female the sperm is received into a pouch in 

 the shell on the under side, between the fourth pair of walking 

 legs. This sperm receptacle is hollowed out in the so-called 

 annulus, or special sternal plate, and in this pouch the sperm re- 

 mains till the eggs are laid. In the crayfish of Europe, how- 

 ever, the sperm conveyed by the stylets is deposited freely over 

 the sternum, in secreted tubules, or spermatophores, and there is 

 no sperm receptacle. 



There are then two forms of indirect sperm transfer within 

 this family, in the two genera Cambarns and Astacits. 



The crayfish of Japan and the Amoor River region are so dif- 

 ferent from other species of Astacns that it is a question whether 

 they do not form a distinct genus. They resemble Cambarns so 

 much that Faxon called them Cambaroides. Nothing is known 

 as to the method of sperm transfer in this Cambaroides subgroup 

 of Astacus, but the following account of the anatomy of the or- 

 gans concerned may aid in a tentative view as to what actual ob- 

 servation of the process may reveal. 



The material used was kindly loaned by the National Museum, 



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