DEVELOPMENT. 



219 



* and that it was a carnivorous, hot-blooded Mammal. Cer- 

 tain structures always co-exist. Animals with two occipi- 

 tal condyles, and non - nucleated blood - corpuscles, suckle 



Fig. 181. 



Fio. 182. 



HOMOLOGIES OP LIMBS. 



Fig. 179.— Arm and Leg of Man, as they are when he gets down on all-fonre. Fia. 



ISO Fore and Hind Legs of Tapir. Fig. 181.— Fore Leg of Seal and Hind Leg 



of Alligator. Fig. 182. — Wing of the Bat. S, scapula j I, ilium, or shin-bone of 

 pelTis; H, hnmerns; F, femur; O, olecranon, or tip of the elbow; P, patella; 

 U, ulna; T, tibia; R, radius; Fi, Fibula; Po, pollex, or thumb; Ha, hallux, or 

 great toe. Compare the fore and hind limbs of the same animal, and the fore 

 or hind limbs of different animals. Note the directions of the homologous seg- 

 ments. 



