244 ELEMENTS OF HISTOLOGY. [Chap. xxxi. 



Numerous sympathetic ganglia, of various sizes, 

 are found in connection with the nerve branches un- 

 derneath the adventitia (peritoneal covering), and in 

 the muscular coat (F. Darwin). The epithelium lining 

 the bladder is stratified transitional, and it greatly 

 varies in the shape of its cells and their stratification, 

 according to the state of expansion of the bladder. 



CHAPTER XXXI. 



THE MALE GENITAL ORGANS. 



321. (1) THE testis of man and mammals is en- 

 veloped in a capsule of white fibrous tissue, the tunica 

 adnata. This is the visceral layer of the tunica 

 vaginalis. Like the parietal layer, it is a serous 

 membrane, and is therefore covered with endo- 

 thelium. Minute villi are occasionally seen pro- 

 jecting from this membrane into the cavity of 

 the tunica vaginalis. These villi are generally 

 covered with germinating endothelium (see par. 33). 

 Inside the tunica adnata, and firmly attached to 

 it, is the tunica albuginea, a fibrous connective 

 tissue membrane of lamellar structure. Towards 

 the posterior margin of the human testis its thick- 

 ness increases, and forms there a special accumu- 

 lation in cross section more or less conical, with 

 posterior basis the mediastinum testis, or corpus 

 Highmori. 



Between the tunica adnata and tunica albuginea 

 is a rich plexus of lymphatics, which, on the one hand, 

 takes up the lymphatics of the interior, and on the 



