4i6 



THE EVOLUTION OF MAN. 



become oviducts, traces of the Wolffian ducts remain, and 

 are known as " Gartner's canals." 



^ y'/ip 1 1 1 /""^■^'* 



Figs. 32d— 326. — Urinary and sexual organs of an embryonic Ox. Fig. 

 324, of female embryo of IJ incli in length ; Pig. 325, of male embryo 

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

 IV, primitive kidney ; irg, Wolff's dnct ; m, Miiller's duct ; m', upper end of 

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

 of nteras) ; g, genital cord ; }>, testes (h', lower, h", upper testis-cord) ; 

 0, ovary ; 0', 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 KoUiker.) 



The most interestino; 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 Miillerian and 



