CH. LVII.] 



THE TESTES. 

 MALE ORGANS. 



793 



The testis is enclosed in a serous membrane called the tunica 

 vaginalis, originally a part of the peritoneum. When the testis 

 descends into the scrotum it carries with it 

 this part of the peritoneum, which then gets 

 entirely cut off from the remainder of that 

 serous membrane. There are, however, many 



Fig. 602. Plan of a ver 

 section of the testicle, 

 showing the arrange- 

 ment of the ducte. The 

 true length and diameter 

 of the aucta have been 

 disregarded, a a, tubuli 

 seminiferi coiled up in 

 the separate lobes ; b, 

 tubuli recti ; e, rete 

 testis ; d, vasa efferent ia 

 ending in the coni vascu- 

 losi ; /, f, g, convoluted 

 canal of the epididymis ; 

 h, vas deferens ; /, section 

 of the back part of the 

 tunica albuginea ; t, t, 

 fibrous processes running 

 between the lobes ; *, me- 

 diastinum. 



Fig. 603. Section of a tubule of the testicle of a 

 rat, to show the formation of the spermatozoa. 

 a, spermatozoa ; b, seminal cells ; c, sustentacu- 

 lar cells, to which the spermatozoa are ad- 

 herent ; d, basement membrane ; , connective 

 tissue. (Cadiat.) 



Fig. 604.- From a section of the testis of dog, showing portions of seminal tubes. A, 

 seminal epithelial cells, and numerous small cells loosely arranged ; 1), the small cell* 

 or spermatoblast* converted into spermatozoa ; 0, groups of these in a further stage of 

 development. (Klein.) 



animals in which the testes remain permanently in the abdomen. 

 The external covering of the testicle itself is a strong fibrous 

 capsule, called, on account of its white appearance, the tunica 



