42 



sects the two testes are separate, each lying in one side of 

 the body-cavity. 



The cephalic end of the united testes is supported by the 

 ligament of the viscera, which is a very slender cord, extend- 

 ing to the dorsal wall of the body. 



Break the envelope enclosing the testes and note that they 

 are composed of many, long, slender tubes ; these are the 

 testicular follicles. 



Separate the two sets of follicles and observe that those of 

 each side empty into a slender duct ; this is the vas deferens. 

 The two vasa deferentia pass caudo-ventrad, one on each 

 side of the alimentary canal. 



Cut in two the alimentary canal between the testes and 

 remove the caudal portion of it. 



Observe the two bundles of tubes which occupy a consid- 

 erable part of the cavity of the abdomen ; these are the semi- 

 nal vesicles and the accessory glands. There is on each side a 

 single, long, much convoluted, accessory gland, and a bundle 

 of shorter, tubular seminal vesicles. The seminal vesicles are 

 reservoirs for the products of the reproductive organs ; the 

 function of the accessory glands has not been determined, 

 they may secrete the more fluid part of the semen. 



Trace out the course of the vasa deferentia, and note that 

 each is joined by the seminal vesicles, and the accessory 

 gland of the same side, and that almost immediately the tubes 

 of the two sides unite, forming a single tube ; this is the 

 ejaculatory duct. 



The ejaculatory duct leads to the penis ; owing to the 

 muscles surrounding this organ the determination of its form 

 is quite difficult, and will be omitted in this elementary course. 

 If fresh specimens are available, kill one in a cyanide bot- 

 tle, and by pressure of the abdomen force out the caudal end 

 of this organ, and observe the chitinous hooks with which it 

 is armed. 



