GENERATIVE ORGANS. 



515 



the so-called os penis (Carnivora, Rodentia), may also be de- 

 veloped, especially frequently in the glans. The glans, which 

 is formed by the corpus cavernosum urethrae (Fig. 269, E), 

 and which is bifid only in exceptional cases (Monotremata, 

 Marsupialia,) varies greatly in its form, and lies retracted in a 

 reduplication of the skin (foreskin or prepuce) which is richly 

 glandular (gl. tysonianae). 



Female sexual organs. The ovaries (Fig. 270) are unsym- 

 metrical only in the Monotremata, in consequence of the reduc- 

 tion of the right ovary. In all other cases they are equally 



FIG. 270. Female generative organs, a of Ornitfiorhynchus (after Owen) ; b of Viverra 

 genetta ; c of Cercopithecus nemeslrinus ; D intestine ; F opening of ureter ; H urinary 

 bladder ; Kl cloaca ; M mouth of uterus ; Ov ovarv ; S urinogenital sinus ; T oviduct 

 U uterus ; Ur ureter ; V vagina. A style is passed through the opening of the intestine 

 into the cloaca in a. 



developed on either side ; they are placed in folds of the peri- 

 toneum, close to the funnel-shaped dilated mouths of the ovi- 

 ducts, by which they are sometimes completely surrounded. 

 The oviduct is divided into (l)the fallopian tube, which is always 

 paired and begins with a free ostium ; (2) the dilated, sometimes 

 paired, more frequently unpaired, middle portion the uterus ; 

 and (3) the terminal part, or vagina, which is unpaired, except in 

 marsupials, and opens behind the opening of the urethra into the 

 short urinogenital sinus, or vestibule. In the Monotremata the 



