COMPARATIVE ANATOMY OF THE UROGENITAL SYSTEM 289 



2. The female reproductive system.— This consists of a pair of ovaries and 

 their ducts. The ovaries are very small oval bodies located at the sides of the 

 peritoneal cavity at the anterior end of the coils of the uterus. Each will be 

 seen to bear little clear vesicles, the Graafian follicles, each of which contains 

 an egg or ovum; in pregnant females the ovary also bears little hard lumps, 

 the corpora lutea, which represent follicles from which the eggs of the pregnancy 

 were discharged. The ovary is suspended by the mesovarium, which extends 

 forward to the kidney and is continuous posteriorly with the ligament of the 

 uterus. 



The ducts of the ovaries are, as in other vertebrates, the Mullerian ducts or 

 oviducts, but they are differentiated into several distinct parts in mammals. 

 The uppermost portion of the oviducts is a slender convoluted tube which 

 passes lateral to the ovary and curves over its anterior end; its mesentery, the 

 mesosalpinx, forms a sort of hood, partly inclosing the ovary. This portion of 

 the oviduct is the uterine or Fallopian tube. It opens in front of the ovary 

 (rabbit) or to the lateral side of it (cat) by the ostium having fringed borders, 

 the fimbriae. On tracing the uterine tube posteriorly it is found to widen 

 suddenly into a thick- walled tube, the uterus (rabbit) or horn of the uterus (cat) . 

 The size of this depends on whether the animal is pregnant or not; in pregnant 

 animals the uteri or horns are greatly enlarged and exhibit a series of swellings, 

 each of which contains an embryo (these will be examined later). The strong 

 fold of peritoneum supporting the uteri or horns is the mesometrium. Mesova- 

 rium, mesosalpinx, and mesometrium together are called the broad ligament of 

 the uterus in mammals. The round ligament of the uterus is the fold extending 

 from the beginning of the uterus or horn posteriorly to the body wall; it is con- 

 tinuous with, but at right angles to, the broad ligament. In the cat the two 

 horns of the uterus unite in the median line, dorsal to the bladder, to a single 

 tube, the body of the uterus. Body and horns together constitute the uterus or 

 womb, but the young develop only in the horns. In the rabbit the two uteri are 

 separate along their entire lengths, and consequently there is no division into 

 body and horns. In the cat the body of the uterus continues posteriorly as the 

 vagina; in the rabbit the two uteri join the vagina; the vagina is a tube situated 

 in the median line between the bladder and the rectum. It exits through the 

 ring formed by the pelvic girdle and vertebral column. 



The external genital parts or external genitalia were described with the 

 external anatomy. Review this (p. 29). Then in the rabbit make an incision 

 through the skin forward from the vulva. In the median line beneath the skin 

 is a hardened body, the clitoris, homologous with the penis of the male. Its 

 anterior end is attached by ligaments to the ischium and pubic symphysis. Cut 

 across the clitoris and note the two cavernous bodies of which it is composed. 

 In the cat the clitoris is minute. 



