354 



THE CAT. 



[CHAP. x. 



(Fig. 158, B). The two upper ends of the Mullerian ducts, above 

 where they begin to form the uterine cornua, open at their deep 

 ends, as already described, thus becoming the Fallopian tubes, 

 which lead from the peritoneal cavity into the uterus. 



The fundamental similarities of the parts in the two sexes may 

 be expressed as follows (Fig. 158, A, B, C) : the primitively formed 

 Wolffian body becomes in the male the vasa efferentia and coni 

 vasculosi, otherwise it vanishes, save that the vas dberrans and 

 hydatid of Morgagni, with the organ of Giraldes,* may be its more 

 or less persistent relics. In the female both the Wolffian body and 

 its duct practically disappear, the parovarmm and Gaertner's duct 

 being persistent remnants of them. In the male the Wolffian duct 

 becomes the vas deferens. The Mullerian ducts, on the contrary, 

 entirely disappear, except that the relics of their conjoined ends 

 persist as the utricle or simi-s pocularis ; while in the female, the 

 Mullerian ducts become the oviducts, the uterus and the vagina. 

 Thus the utricle is the minute male uterus. The small body formed 

 on the front margin of the cloaca becomes in the male the penis, 

 the clitoris in the female. The groove which traverses it below and 

 behind, closes in, in the male, to form the spongy urethra ; in the 

 female it remains open. The folds of integument which lie on each 

 side of the urogenital aperture, persist as such folds in the female, 

 but, in the male, unite ventrally in the middle line to form the 

 scrotum. The glands of Bertholin correspond with those of Cowper, 

 but the prostate of the male has no, as yet discovered, analogue in 

 the female. 



The development of the spermatozoa has been already described, 

 together with the description of the testis.f OVA arise simply as 

 epithelial cells, such as those which invest the incipient ovary, and 

 generally line the peritoneal cavity. They also arise as (and from 

 amongst) epithelial cells more deeply placed in the ovary ; but it is 

 not certain whether such deeper cells arise inside quasi-glandular 

 tubes formed of inflected superficial epithelium, or whether they are 

 deep-seated because the connective tissue stroma of the ovary has 

 grown outwards and enclosed them.| The ordinary sized germ- 

 epithelial cells are about ^-sVo f an i ncn i* 1 diameter. The sub- 

 stance of the ovary by which these cells become enclosed, is an 

 outgrowth from the Wolffian body. 



The epithelial cells become thus enclosed in groups or " nests," 

 and some of them, enlarging in size and acquiring much clear 

 protoplasm around their nucleus, become what are called primitive 

 or primordial om, which average about T oVo- of an i ncn i n diameter. 

 Other adjacent epithelial cells divide and multiply, and form a 



* See ante, pp. 244 and 250. 



i 1 See ante, p. 245. 



J As is the opinion of Mr. F. Balfour. 

 See Quarterly Journal of Microscopic 

 Science, October, 1878, p. 418, and 

 Embryology, vol. i., p. 47. See also a 



paper by Dr. Foulis, in the Trans, of 

 the Roy. Soc. of Edinb., vol. xxvii., 

 p. 345, and another by Mr. E. A. 

 Schafer, on the Pro. Eoy. Soc., 1880, 

 p. 245. 



