92 MAN AND THE LOWER ANIMALS n 



circling zone, while in Man, the allantois remains 

 comparatively small, and its vascular rootlets are 

 eventually restricted to one disk-like spot. Hence, 

 while the placenta of the Dog is like a girdle, that 

 of Man has the cake-like form, indicated by the 

 name of the organ. 



But, exactly in those respects in which the 

 developing Man differs from the Dog, he resembles 

 the ape, which, like man, has a spheroidal yelk-sac 

 and a discoidal, sometimes partially lobed, placenta. 

 So that it is only quite in the later stages of 

 development that the young human being presents 

 marked differences from the young ape, while the 

 latter departs as much from the dog in its devel- 

 opment, as the man does. 



Startling as the last assertion may appear to be, 

 it is demonstrably true, and it alone appears to 

 me sufficient to place beyond all doubt the 

 structural unity of man with the rest of the 

 animal world, and more particularly and closely 

 with the apes. 



Thus, identical in the physical processes by 

 which he originates identical in the early stages 

 of his formation identical in the mode of his 

 nutrition before and after birth, with the animals 

 which lie immediately below him in the scale 

 Man, if his adult and perfect structure be com- 

 pared with theirs, exhibits, as might be expected, 



