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12 Fauna Americana. 



slightly convex ; the line formed by the surface 

 of the lower series slightly concave. Incisors 

 proceed in a direction more or less vertical with 

 the maxillary bones ; the two middle ones of the 

 upper jaw are broadest ; inferior incisors nearly 

 equal, the two exterior rather broadest ; canines 

 in either jaw, not projecting, with their summits 

 more or less obtusely triangular; the two first 

 molars in either jaw are the smallest, their crowns 

 furnished with two blunt tubercles, one internal, 

 the other external ; the three remaining molars 

 nearly equal, those of the upper jaw have the 

 crowns furnished with three tubercles; two on 

 the outer, one on the inner side ; the crowns of 

 the inferior, with generally four tubercles, two on 

 the outer, two on the inner side. 



Superior extremities terminated by a hand ; an 

 organ eminently prehensile, and susceptible from 

 its structure of a greater variety of motions than 

 that of any other animal; five-fingered; thumb 

 possessing the power of motion in all directions, 

 independent of the fingers ; fore-arm shorter than 

 the arm. 



Inferior extremities constructed for the upriglit 

 posture only ; the feet at right angles with the 

 legs ; five toes, with broad flat nails ; sole, more 

 or less arched, the weight of the body being sup- 

 ported chiefly, by the os calcis, and extremities of 

 the tarsal bones, the posterior borders of the for- 

 mer resting firm and flat upon the ground. 



