354 SPLANCHNOLOGY. 



to consist of an attached and a free portion ; the first origi- 

 nating at the ischial arch, in the pillars, or crura penis, and 

 terminating before the brim of the pubis, where the free portion 

 commences. 



The substance of the penis is formed of what is called erectile 

 tissue, a tissue which, under certain circumstances, becomes 

 enormously distended with blood. The erectile structures are 

 two in number, the corpus cavemosum and the corpus 

 fipongiosum. 



The corpus cavemosum, much the larger of these structures, 

 forms the superior and lateral portions of the penis ; it is divided 

 by an imperfect fibrous partition, the septum pectiniforme, into 

 two lateral halves, which may be regarded as separate corpora 

 cavernosa. This septum is thick and complete behind, gradually 

 thinning as it approaches the free extremity of -the penis, where 

 it only imperfectly separates the halves. It consists of simple 

 vertical bands, similar to the teeth of a comb, extending from 

 above downwards. The corpora cavernosa are invested by a 

 strong elastic fibrous tunic, whence spring trabeculse, which 

 divide it into numerous compartmente, giving it a cavernous 

 appearance ; in these caverns are cells, which receive the blood 

 during erection of the organ. The upper surface between the 

 cavernous bodies is grooved for the dorsal vessels ; the inferior 

 aspect is also grooved, and lodges the corpus spongiosum. The 

 corpora cavernosa recede from each other posteriorly, forming the 

 pillars, or crura penis, which are attached to the ischial arch, 

 and are crossed by the erectores muscles, which blend with 

 them ; anteriorly they terminate in blunt points behind the. gla.ns 

 penis. The penis is attached to the symphysis pubis by two 

 suspensory ligaments, which spring from the corpora cavernosa. 



The corpus spongiosum encloses the urethra, is situated in the 

 inferior groove of the corpora cavernosa, and surrounded by the 

 accelerator muscle. It commences between the crura by an 

 enlarged portion, the bulb of the penis, and passes down the 

 groove until it reaches the anterior extremity, where it expands 

 to form the glans. The spongiosum is enclosed in a fibrous 

 tunic, similar to, but more delicate than, that of the cavernosa. 



The glans forms the terminal extremity of the penis, and is an 

 enlargement of the corpus spongiosum. At its apex is a deep 

 fossa, in the centre of which lies the meatus urinarius, bounded 

 by two prominent lips. Ifc terminates posteriorly by a con- 



