678 THE LAST STEPS IN THE GENEALOGY OF MAN. 



the hinder ones more. Following the marsupials, evolution commences, 

 specializations take place in different directions. 



Among the galeopitheci and the cheiroptera, the particular adap- 

 tation works in the way of flight, one part or the whole limb is not only 

 transformed, but bends itself to the needs and obeys the calls upon it. 



Among the ungulates, the adaptation works in the way of locomotion 

 by the four limbs, exclusively; gradually these mold themselves on 

 the same type, the useless bones disappear, or are fused together, cer- 

 tain superfluous movements cease in the ratio that others increase, 

 including the necessary corresponding anatomical arrangements. Here 

 Broca ought to have taken his model type of the locomotive limb, as 

 among man he possessed the model type of the prehensile limb. 



Among the carnivoni, that have to bound over the earth to catch 

 their prey while at the same time they must be able to seize, hold, and 

 rend it, the fore paws have remained perfect locomotive organs, but at 

 the same time, organs of attack by their claws, and organs of prehen- 

 sion to a certain extent, — particularly in the anterior extremities. 



Among the monkeys an adaptation of another kind has taken place. 

 Those from whom they descend lived in the trees, ran on the branches; 

 they had need of increasing their power of prehension ; tliey had to 

 clasp the rounded trunks of trees and catch the branches in passing 

 from one to the other. The adaptation appears to show in the jiosterior 

 members first; later in the anterior ones. The make-up of the limb 

 has not had to lose its own type on that account; it is enough that the 

 extremities are adapted in a certain way. The nails, the free oppos- 

 able thumb, the very movable fingers, are enough ; nature is contented 

 with that without mounting to the higher segment. 



One fine day a revolution takes place. In the same wfiy as an adap- 

 tation to an arboreal life lias taken place at the expense of other prior 

 species, so an adaptation 1o terrestrial life occurred with an upright 

 attitude, favorable to a more extended vision, a diminution of the 

 olfactory sense and the facial proniinence over which it presides, a 

 perfecting of touch, and above all intelligence. From that time all the 

 living forces of adaptation have tended towards the same end, the lower 

 thumb has ceased to be opposable, the other toes liave decreased in 

 length, what the foot loses the hand gains; man was.created exclusively 

 two handed above, exclusively two footed below, all the accessory 

 parts in the segments of the limbs agreeing with the types, which had 

 existed since the marsupials but less accentuated until then. 



The little character of the opposable thumb brought out byCuvier, 

 marks then perfectly that which is common and special among the 

 monkeys, the ability of clasping limbs of trees by the four extremities. 

 Without doubt he expressed but one of the particulars of that make- 

 up so perfect in man, who has given birth to the words hand and foot, 

 but it is an essential one. One does not know enough to deny however 

 that the second character necessary to the function of prehension, that 



