THE EVOLUTION OF MAN. 



become oviducts, traces of the Wolffian ducts jremain, and 

 are known as " Gartner's canals." 



FIGS. 324-326. Urinary and sexual organs of an embryonic Ox. Fig 

 324, of female embryo of 1J inch in length ; Fig. 325, of male embryo 

 of 24 inches in length* Fig. 326, of female embryo of 2 inches in length : 

 w, primitive kidney ; wg, Wolff's* dnct ; m, Miiller's duct ; TO', npper end of 

 he latter (opened at <); t, lower thickened end of the same (rudiment 

 of uterus) ; g, genital cord ; h, testes (h' y lower, h", upper testis-cord) ; 

 o, ovary ; o', lower ovary-cord ; i, groin-cord of the primitive kidney ; 

 d, diaphragm-cord of the primitive kidney ; n, permanent kidneys (below 

 these the S-shaped urine-duct ; between the two the rectum) ; v, urine- 

 bladder ; a, navel-artery. (After Kolliker.) 



The most interesting facts in reference to this remark- 

 able development of the primitive kidney ducts and their 

 union with the sexual glands are exhibited in Amphibia 

 (Figs. 321-323). The first rudiment of the primitive kidney 

 ducts and their differentiation into the Mullerian and 



