THE CRAYFISH AND ARTHROPODS IN GENERAL 



The spermatozoa remain in the testis and vasa deferentia 

 until copulation takes place. As many as two million sperma- 

 tozoa are contained in the vasa deferentia of a single specimen 



(158). 



FEMALE REPRODUCTIVE ORGANS. The ovary resembles 

 the testis in form, and is similarly located in the body 

 (Fig. 1 08). A short oviduct (i) leads from near the 

 center of each side of the ovary to the external aperture in the 

 coxopodite of the third walking leg (4, 5). 



OOGENESIS. The primitive germ cells in the walls of the ovary 

 grow in size, become sur- 

 rounded by a layer of 

 small cells, the follicle, 

 which eventually break 

 down, allowing the eggs to 

 escape into the central 

 cavity of the ovary. At 

 the time of laying the ova 

 pass out through the ovi- 

 duct. 



Breeding Habits. The 

 details of copulation, egg- 

 laying, and the larval 

 stages of Cambarus have 

 only recently been made 

 out, and even now our 

 account must be derived FlG - Io8 - Female reproductive organs 



of the crayfish, i, right oviduct ; 



from observations of 

 several different species, 

 since the entire life his- 

 tory of a single species 

 has never been recorded. 

 The development of the eggs of Cambarus from the time of 

 deposition to the time of hatching has likewise never been 

 investigated. 



2, right lobe of ovary ; j, left lobe 

 opened to show central cavity ; 4, ex- 

 ternal opening of oviduct ; 5, base of 

 third walking leg. (From Shipley and 

 MacBride.) 



