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. 



PIG. 182. 



HOMOLOGIES OF LIMBS. 



PIG. 179. Arm and Leg of Man, as they are when he gets down on all-fours. Pio. 

 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 ; I, ilium, or shin-bone of 

 pelvis; H, humerns : F, femur; O, olecranou. 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. 



