THE ABDOMEN. 243 



spongy portion is completely invested by tlie corpus spon- 

 giosum of the penis, and anteriorly dilates, forming the 

 widest joortion or fossa navicularis, prior to terminating in 

 its narrowest ]jortion, meatus urinarius extermis. A catheter 

 which will pass through here will pass along any portion 

 of the canal, unless obstructed by foreign matter. 



The prostate gland is a body which embraces superiorly 

 and laterally the neck of the bladder. It is divided into 

 two lateral, and a connecting isthmus or middle lohe. This 

 gland is racemose in its nature, and pours its secretion 

 through the above described openings into the urethra. 

 Cowper's glands are two in number, and are covered by 

 Wilson's muscle ; they resemble the prostate in structure. 

 The function of these glands is but little known. Their 

 secretion, by mixing with the semen, is considered to in- 

 crease its efficacy. The prostate gland hides from view 

 the terminal portion of the vas deferens, and of the duct 

 of vesicula seminalis and the ejaculatory duct. 



The penis is a dense elongated organ extending from 

 the posterior part of the ischium in a forward direction 

 under the symphysis of the ossa innominata. It is mainly 

 composed of the corpus cavernosum. This is situated 

 at the superior part, and presents a supero-lateral surface, 

 rounded and covered by a plexus of veins, an inferior sur- 

 face concave forming a groove through whrch the urethra 

 (spongy) runs, surrounded by corpus spongiosum. Ante- 

 riorly it presents two sharp points, which are concealed by 

 the glans penis; posteriorly, by bifurcation, it produces 

 the crura, dense, yellowish, fibrous bands running to be- 

 come attached to the tuberosities of the ischium, which are 

 surrounded by the erectores penis muscles, arising from 

 the tuberosities of the ischium and becoming inserted into 

 the root of the penis. On transverse section this organ 

 will be found to present a tendency to division into two 

 parts. It has externally a thick layer of yellow elastic 

 tissue, from which trabeculae and bands are sent inwards, 

 which, by their union and reunion, produce spaces, which 

 are occupied by venous sinuses. The most remarkable of 

 these septa projects from the central line at the superior 

 part. It consists of a number of bands running down- 

 wards, resembling in arrangements the teeth of a comb, 

 septum pectiniforme. 



The penis anteriorly receives blood from the external 



