CHAPTER V.

PROOFS FROM HOMOLOGIES OF THE VERTEBRATE SKELETON.

_Common general plan_--In several respects--Strongly suggestive of common origin--Details of structure demonstrative of the same 111

_Special homology of vertebrate limbs_ 113

_Fore-limbs_--Comparison of fore-limbs of mammals, birds, reptiles, and fishes, part for part--Gradual changes in collar-bone and coracoid--In position of elbow--In bones of forearm--In position of wrist--In the tread--The term manus--Number of toes--Modifications for flight in various animals--For swimming in whales and fishes 113

_Hind-limbs_--Comparison of hind-limbs of several mammals-- Position of knee--Of heel--Plantigrade and digitigrade --Degrees of the latter--Number of toes--General law in regard to number of similar parts--Order of toe-dropping in artiodactyles--In perissodactyles 121

_Genesis of the horse_--Changes in foot-structure--Same true of other parts of skeleton--Only natural explanation is derivation--Nature compared with man in mode of working-- Angels--Griffins--Centaurs--Muscular and nervous systems --Visceral organs 126