420 



THE EVOLUTION OF MAN. 



naculum testis) (Fig. 328, M, gli) ; in the female, the round 

 uterus-cord (Fig. 328, F,r). In the latter the ovaries 

 migrate more or less in the direction of the small pelvis, or 



FIG. 328, N. 



FIG. 328, F. 



FIG. 328. Original position of the sexual glands in the abdominal cavity 

 of the human embryo (of three months). Fig. 328, M, male (natural size) : 

 h, testis ; gh, the condncting-cord of the testis ; wg, seed-duct ; b, urinary 

 bladder ; uh, lower hollow vein (vena cava) ; nn, supplementary kidneys ; 

 n, kidneys. Fig. 328 F, female (somewhat enlarged) : r, round uterus-cord 

 (below this the urine-bladder, above it the ovary) ; r', kidney ; s, sup- 

 plementary kidney ; c, blind-intestine (caecum) ; o, small net ; om, large 

 net (between the two is the stomach) ; I, spleen. (After Kolliker.) 



even enter this. In the male the testis quits the abdominal 

 cavity altogether, passing through the groin-canal, and 

 enters a sac-shaped, distended fold of the external skin- 

 covering. The coalescence of the right and left folds 

 (" sexual folds ") gives rise to the testis-sac (scrotum). The 

 various Mammals exhibit the various stages of this migra- 

 tion. In the Elephant and in Whales the testes descend 

 very little, and lie below the kidneys. In many Gnawing 

 Animals (Rodentia) and Beasts of Prey (Carnaria) they 

 enter the groin-canal. In most higher Mammals they pass 

 down through this into the testis-sac ; usually the walls of 



