308 EXTERNAL GENERATIVE ORGANS, BY E. KLEIN. 



of the urethra are vascular, and possess a single or, as in those 

 of the fossa navicularis, several capillary loops. When the 

 papillae are absent, as in those parts invested by columnar 

 epithelium, there is a close subepithelial capillary plexus dis- 

 tributed immediately beneath the surface. The mucous mem- 

 brane is looser, and consists of a delicate meshwork of con- 

 nective tissue, in which small isolated longitudinal and oblique 

 fasciculi of smooth muscular fibres are everywhere found, that 

 proceed from the muscular trabeculse of the corpus cavernosum 

 urethrse (corpus spongiosum). 



The mucous glands of Littre are tolerably abundant, espe- 

 cially upon the upper wall. They form sinuous canals, perfo- 

 rating the mucous membrane obliquely, and having a diameter 

 of 0*13 of a millimeter. The epithelium of the surface of the 

 mucous membrane is continued for a little distance into their 

 interior. These tubes are undivided until they enter the sub- 

 stance of the corpus cavernosum, where they present four or 

 five hemispherical dilatations or acini ; the latter have a dia- 

 meter of 0'08 to 0'12 of a millimeter, and are not unfrequently 

 in contact with the albuginea of the corpus cavernosum 

 urethrse (corpus spongiosum). The epithelium of the greater 

 part of the excretory duct and of the acini consists of a single 

 layer of columnar cells. In the epithelial cells of the acini, the 

 nucleus, even in the newly born child, is by no means every- 

 where spheroidal, but is flattened as in adults, with its long 

 axis at right angles to that of the cell, and in immediate contact 

 with the membrana propria. 



As the greater part of these glands everywhere lie between 

 the vessels of the corpus cavernosum, and are consequently 

 surrounded by muscles, it is quite obvious that the erection 

 of the organ must exert a considerable influence on the dis- 

 charge of their secretion, whilst it may also influence its 

 production. 



The lymphatics of the urethra are moderately numerous; 

 they lie in the mucous membrane near the epithelium, run 

 parallel to the long axis of the canal, and communicate freely 

 by means of transverse and oblique anastomosing branches. 

 They attain their greatest development on the lower wall of 

 the fossa navicularis. 



