THE UROGENITAL SYSTEM 263 



middle line beneath the pelvic symphysis. This band divides 

 distally, and its halves ensheath the glans and thus form a sup- 

 port of the penis. 



The penis is formed by three bodies, the two corpora 

 cavernosa penis and the single corpus cavernosum urethras 

 (corpus spongiosum). 



The corpora cavernosa penis (Fig. \\i, j). Each is a 

 cylindrical sheath of dense fibrous tissue within which are 

 trabecular separating blood-sinuses. Each corpus cavernosum 

 is attached by the one pointed end to the caudal border of the 

 ramus of the ischium near the symphysis. From their attach- 

 ments the corpora cavernosa approach one another, forming 

 the crura of the penis. They become closely united by their 

 medial surfaces and pass thus to the free end of the penis where 

 their somewhat pointed distal ends are imbedded in the 

 glans {i)i). A groove is left between the corpora cavernosa on 

 the dorsum of the penis, and there is a second groove on the 

 ventral side. In the latter groove lies the urethra. 



The corpus cavernosum urethras is the spongy portion of 

 the urethra^ which lies in the groove on the ventral surface of 

 the penis, between the corpora cavernosa penis. It becomes 

 greatly enlarged at the distal end of the penis, forming the 

 glans (;//). A small bone (os penis) is imbedded in the distal 

 end of the penis. 



1^. Fkmale Genital Organs (Fig. 112). — The urinal 

 organs of the female are like those of the male. The neck (/t) 

 of the bladder is, however, much longer, extending almost to 

 the border of the ischiatic ramus. The urethra is consequently 

 short. 



The genital organs consist of the ovaries (c) (the organs 

 which produce the eggs), the oviducts or uterine tubes (e-) 

 (Fallopian tubes), which receive the eggs from the ovaries; a 

 bifid uterus (/and /) in which the ova undergo their develop- 

 ment, and a vagina (m) which leads from the utorus to its 

 junction with the neck of the bladder. 



The neck of tl"^^ bladder (k) unites with the vagina to form 

 the urogenital sinus («) which is very short, leads to the 

 external opening, and is comparable to the male urethra. 



