DEVELOPMENT 



431 



mals. All ruminant hoofed beasts have horns and 

 cloven feet. If the hoofs are even, the horns are even, 

 as in the ox ; if odd, as in the rhinoceros, the horns are 



FIG. 377. 



FIG. 37 8, 



HOMOLOGIES OF LIMBS 



FIG. 375. Arm and Leg of Man, as they are when he gets down on all fours. 

 FIG. 376. Fore and Hind Legs of Tapir. FIG. 377. Fore Leg of Seal and Hind 

 Leg of Alligator. FIG. 378. Wing of the Bat. S, scapula ; I, ilium, or rim-bone 

 of pelvis ; H, humerus ; 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 segments. 



