THE EVOLUTION OF MAN. 



but even in Pouched Animals (Marsupialia) a connection 

 forms between the two Mullerian ducts, and in Placental 

 Animals they coalesce below with the rudimentary Wolffian 

 ducts, forming with them a single 

 "sexual cord" (funiculus geni- 

 talis). But the original indepen- 

 dence of the two parts of the 

 uterus, and of the two vagina 

 canals which proceed out of their 

 lower extremities, persists in many 

 lower Placental Animals, while in 

 the higher members of the same 

 group, these organs gradually 

 coalesce to form one single organ. 



FIG. 327. Female sexual The process of Coalescence ad- 

 organs of a Beaked Animal vance s steadily from below (or 



(Ornithorhynchvs, Figs. 195, _ , . 



196): o, ovaries; t, oviduct; from behind) upwards (or for- 

 u, uterus ; sug, urinary sexual wards). While in many Gnawing 

 cavity (sinus vrogenitaUs); the AnimaJfl ( Ro dentia,e.g., Hares and 



two parts of the uterus open 



into .this at u' . d, cloaca. Squirrels) two separate uteri open 



(After Gegenbaur.) into the vag i na cana l w hich has 



already become simple, in other Gnawing Animals, as also 

 in Beasts of Prey, Whales, and Hoofed Animals (Ungulata), 

 the lower halves of the two uteri are already coalescent, 

 their upper halves (the so-called horns, "cornua") remaining 

 distinct (" uterus bicornis "). In Bats and Semi-apes these 

 upper horns are very short, while the unified lower part 

 becomes longer. Finally, in Apes, as in Man., the cohesion 

 of the two parts is complete, one simple pear-shaped uterus- 

 pouch alone remaining, and into this the oviducts open on 

 each side. 



