334 



DISCOVERY REPORTS 



a small mass of chitin in the enlarged part of the ducts ej behind the external opening. 

 It is of the same shape as the full-sized spermatophore, but whether it contains active 

 spermatozoa seems doubtful (Fig. 6). 



After some further growth, the mature condition is reached (Figs. 7 and 8). The 

 follicles of the testis are often difficult to distinguish separately, because they are very 

 tightly packed together. The horseshoe-shaped band, formerly regarded as part of the 

 vasa deferentia, was shown by Raab (191 5) to be filled with germinal tissue even in 

 quite young specimens, and is therefore more correctly considered to be part of the testis. 



t qf\ g vd [p pf\ sps 



Fig. 6. Dissection to show the development of the male reproductive system, y 15. afl, anterior 

 flexure; ej, ejaculatory duct; ", gut; Ip, lateral pocket; pfl, posterior flexure; sps, spermatophore sac; 

 t, testis; vd, vas deferens. 



Raab (191 5) determined the histology and function of the various parts of the repro- 

 ductive system. He found that in the region of the anterior flexure afl, the lumen of 

 the vasa deferentia is fairly wide and is lined with flattened cells of pavement epithelium. 

 In mature males it is full of spermatozoa. The lumen is not so wide in the region of the 

 posterior flexure pfl, being lined with columnar epithelium and containing, in addition 

 to spermatozoa, a secretion which is the product of the epithelial cells. 



Behind the posterior flexure, where the lateral pocket Ip opens into the duct, the 

 lumen widens again and the epithelium flattens. Chun (1896) called this part of the 

 vas deferens the spermatophore sac sps (Figs. 7 and 8), and in mature specimens a 

 spermatophore in process of formation is to be found in each sac. The spermatozoa, 



