MALE ORGANS OF EEPRODUCTION 481 



simple arched tubules. According to Curtis (1915) branches and 

 anastomoses of seminiferous tubules are infrequent in the mouse testis, 

 more frequent in dog. and most frequent in rabbit. 



The testis is lodged in the scrotum. The wall of the scrotum is 

 essentially like the general integument, except that it may be more 



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FIG. 426. SEMINAL TUBULE OF A MAN IN TRANSECTION. 



a and 6, interstitial cells, the latter containing coarse granules; c, connective 

 tissue cells; d, a mast-cell of the connective tissue. Within the tubule several phases 

 of spcrmatogenesis are well shown. Highly magnified. (After Spangaro.) 



highly pigmented. Its subcutaneous layer, however, is looser in texture 

 and contains more elastic tissue and smooth muscle. It is known as the 

 dart os. 



The wall of the seminiferous tubules consists of fibre-elastic tissue. 

 They are lined with a several layered epithelium, the cells representing 

 the several stages of spermatogenesis. In addition to the germ or sex 

 cells, the epithelium contains sustentacular cells (Sertoli cells), to which 

 the spermatids become attached during process of metamorphosis into 

 ripe spermatozoa (spermia). It seems probable that the spermatids also 



