658 MAMMALIA. 



The uterus masculinus is the homologue of the vagina in 

 the female, and seems to arise from the Miillerian ducts. 

 It opens into the urethra, which runs backwards from the 

 bladder, and the urogenital canal thus formed is continued 

 through the penis. 



Beside the uterus masculinus and the vasa deferentia, 

 there are lobed prostate glands opening by several ducts 

 into the urogenital canal. Behind the prostate, on the 

 dorsal wall of the urogenital canal, lie two Cowper's 

 glands. 



The penis projects in front of the anus behind the pubic 

 symphysis, has vascular dorsal walls (corpus spongiosum), 

 stiff ventral walls (corpora cavernosa), and is invested by a 

 loose sheath of skin — the prepuce. At the side of the penis 

 lie two perineal glands. 



(b) Female. — The ovaries are small oval bodies about 

 three quarters of an inch in length, attached behind the 

 kidneys to the dorsal abdominal wall, exhibiting on their 

 surface several clear projections or Graafian follicles, each of 

 which encloses an ovum. 



The ova, when mature, burst from the ovaries, and are 

 caught by the adjacent anterior openings of the oviducts. 

 The oviducts are modified Miillerian ducts, differentiated 

 into three regions. The anterior portion or Fallopian tube 

 is narrow, slightly convoluted, with a funnel-shaped, fimbri- 

 ated mouth lying close to the ovary. The median portion 

 or uterus is the region in which the fertilised ova become 

 attached and develop. In the rabbit the uterine regions of 

 the two oviducts are distinct, forming what is called a double 

 uterus. In most Mammals the uterine regions of the ovi- 

 ducts coalesce, forming a bicornuate or a single uterus, 

 according to the completeness of the fusion. In all Mam- 

 mals above Marsupials the posterior parts of the two 

 oviducts unite in a median tube — the vagina. 



The vagina unites with the neck of the bladder, and forms 

 the wide but short urogenital canal or vestibule, which 

 opens at the vulva, ventral to the anus. On the ventral wall 

 of the vestibule lies the clitoris, a small rod-like body — the 

 homologue of the penis. On the dorsal wall lie two small 

 Cowper's glands, and there are also perineal glands as in 

 the male. 



