

PEOSTATE GLAND VESICULJ3 SEMINALES. 553 



atics in the glans around the urethra, and running backwards on 

 that canal to the pelvic glands. 



The nerves of the penis from the internal pudic, go to the skin and 

 the mucous membrane of the urethra, and, in 'very small amount, to 

 the corpora cavernosa; while all those from the sympathetic are 

 destined to the latter. The former nerve-fibres terminate like those 

 of the skin generally ; of the terminations of the latter, nothing is 

 known. 



There is an expansion of the corpus spongiosum of the urethra 

 opposite the root of the penis, called the bulb of the urethra ; and 

 behind this is the membranous and then the prostatic portion of 

 the urethra the last being encompassed by the prostate gland. 



The prostate consists partly (one-third to one-half) of glandular 

 substance, and the rest mainly of smooth muscular fibres. 1. The 

 glandular portion consists of 30 to 50 compound racemose glands, 

 generally conical or pyriform, situated principally in the more ex- 

 ternal parts of the organ. The numerous excretory ducts penetrate 

 between the longitudinal and transverse fibres, and open into the 

 urethra on both sides of the caput gallinaginis, which also consists 

 in part of smooth muscular fibres. The casca of the prostate gland 

 are lined by a simple scaly epithelium; their ducts by a conoidal 

 one. 2. The muscular portion of the prostate consists \st, of an 

 external layer of circular fibres continuous with the sphincter ve- 

 sica3, extending as far as the caput gallinaginis; Zdly, of a layer 

 between this and the urethra, composed about equally of areolar 

 tissue and smooth muscular fibres, extending from the vesical tri- 

 angle tojthe caput gallinaginis. The fibrous coat which invests the 

 prostate also abounds in fasciculi of smooth muscular fibres. The 

 secretion of the prostate resembles that of the vesiculce seminales, 

 next to be described. 



2 and 3. The vesiculce seminales (Fig. 382), with the ejaculatory 

 ducts, and the vasa deferentia, have essentially the same structure; 

 consisting of an external fibrous tunic, then a layer of smooth mus- 

 cular fibres, and internally a mucous membrane. The walls of the 

 vesiculaB seminales are much thinner than those of the vasa defe- 

 rentia ; the latter being ^4 to Jg of an inch thick, while their whole 

 diameter is ^ to \ of an inch, and their cavity, or lumen, ^ to -^ of 

 an inch. The ejaculatory ducts commence from the prostatic portion 

 of the urethra on each side of the caput gallinaginis, and become 

 continuous on the one hand with the vesiculae seminales, and on the 



