190 



EIGHTEENTH LECTURE. 



mation. Their cells are cylindrical, but become lower in the 

 efferent canal-work. 



The male urethra presents a pars prostatica, a consecutive 

 membranous middle portion (pars membranacea), and a 

 terminal division running through the penis (pars cavernosa). 

 The latter portion is surrounded by a cavernous tissue (corpus 

 spongiosum urethrce), which takes the shape of the glans an- 

 teriorly. Two similar cavernous structures, the corpora cav- 

 ernosa penis, are added. 



The mucous membrane of the urethra has at first flattened, 

 and further downwards cylindrical cells. It is surrounded 

 by loose connective tissue, which might be called cavernous in 

 consequence of its great vascularity, and over this there are 

 smooth muscles. Racemose glandules occur in the prostatic 

 portion, as well as in the colliculus seminalis. The mucous 

 membrane presents folds. In the middle and lower portions 

 the muscular coating diminishes more and more. The mucous 

 membrane of the lower portion contains excavations (lacunae 

 Morgagnii) and small, undeveloped Littre's mucous glandules. 

 Towards the orifice of the urethra stratified flattened epithe- 

 lium again commences. 



The skin of the penis, thin and flaccid, has a loose subcuta- 

 neous cellular tissue, free from fat, and permeated by smooth 

 muscular fibres. An extensible connective tissue, free from 

 fat, unites the two plates of the prepuce ; it also contains mus- 

 cular elements. 



The thin skin of the glans has numerous papillae, which dis- 

 appear in the epithelial covering ; the inner, mucous-mem- 

 brane-like surface of the prepuce also shows such papillae. 



The Tyson's glands occur on the inner surface of the pre- 

 puce, occasionally also on the glans, especially on the frenu- 

 lum. They participate in a very subordinate manner in the 

 formation of the fatty smegma praeputii. 



Let us also mention, in conclusion, the structure of tile 

 corpora cavernosa. These structures are surrounded by a 

 firmer, elastic element, which is however poor in muscular 

 elements, a so-called albuginea. It sends off innumerable 



