Elbow- 



Wrist, 



Man 



Vulture 



Whale Halibut 



Man 



Wolf Ostrich 



Duck 



Crocodile 



Seal 



HOMOLOGIES IN FORE LIMBS AND IN HIND LIMBS OF VERTEBRATES 



Walking, crawling, swimming, flying — all the various modes of locomotion found 

 among backboned animals — are carried on by organs having the same fundamen- 

 tal structure 



in other mammals too — in the bat, for example, or the kangaroo. But 

 among the primates the human hand stands out, with its distinct thumb 

 and the possibilities for fine "handling" of objects. 



49 



