STRUCTURE OF THE PENIS. 311 



The corpus cavernosum urethrse is more strongly developed 

 upon the lower than upon the upper segment. The large 

 cavernous spaces extend in the latter up to the tunica albu- 

 ginea, whilst in the lower, and partly also in the lateral por- 

 tion, an almost continuous muscular layer lies between a kind 

 of cortical vascular layer and the principal mass of the corpus 

 cavernosum, which is only interrupted by a few vessels pro- 

 ceeding from the cortical layer to the interior. A similar 

 arrangement occurs in the corpus cavernosum penis ; the 

 largest spaces are in the centre ; from thence towards the peri- 

 phery in each half they rapidly diminish in size, becoming 

 gradually replaced by a layer consisting almost entirely of 

 muscular fibres, whilst still more externally they form a cor- 

 tical layer in immediate contact with the albuginea. 



The cavities diminish but little in size from the centre of 

 each corpus cavernosum towards the septum. Those of each 

 corpus lying close to the septum communicate with one an- 

 other by oblique and transverse anastomoses, which are accom- 

 panied by corresponding transverse connecting trabeculse of 

 muscular fibres. 



Proceeding from the corona glandis towards the anterior ex- 

 tremity of the penis, the corpus cavernosum urethrse gradually 

 diminishes in thickness, attenuating first upon the upper and 

 then upon the lower wall. A few transverse branches still 

 exist on the upper part, that establish a communication be- 

 tween the vascular cavities of the two sides ; in the lower part 

 a connective-tissue septum, corresponding to the frsenulum 

 prseputii, penetrates its substance, so that anteriorly the corpus 

 cavernosum urethrse appears to be divided from below into two 

 segments. Such connective-tissue structures sometimes, like a 

 complete tunica albuginea, divide off an elliptical area within 

 the corpus cavernosum urethrse, so that a small corpus caver- 

 nosum appears to be present on each side within the corpus 

 cavernosum urethrse. Just as the corpora cavernosa penis 

 terminate with conically pointed extremities in the glans, 

 the corpus cavernosum urethrse begins also to lose its indi- 

 viduality, and becomes completely fused with the corpus caver- 

 nosum of the glans. This presents a fissure below, and in the 

 vicinity of the orificium urethrse it is divided by the entrance 



