THE HUMAN FORM 319 



three premolars in the upper jaw, even when the total number 

 of teeth is only thirty-two, whereas the Old World Monkeys 

 have only two. This is considered to be an argument in favour 

 of the greater antiquity of the American Monkeys. 



From the numerical point of view the dentition of Man 

 resembles that of the Old World Monkeys ; it differs chiefly 

 in the smaller size of the canines. The reduction in the formula 

 continues as the ascent is made from Lemurs to Man, in whom 

 it reaches its minimum limit of thirty-two teeth, already 

 attained in the catarrhine Monkeys. We can only seek 

 the cause of this reduction in a character common to all 

 these animals, and the most logical to which we can 

 attribute it is the faculty of prehension acquired by 

 the hand, which thus relieves the jaws of a great deal of 

 the work that had hitherto exclusively devolved upon them. 

 Thenceforth, having no longer to exercise traction in the 

 seizure and removal of objects, and being no longer stretched 

 by this traction— which counted for at least one important 

 factor in their peculiar elongation, and no doubt provoked the 

 special conformation of the herbivorous head — the jaws became 

 shorter and more compact. Thus was the passage effected 

 from the fox-like muzzle of the Lemur tribe to the flat-nosed 

 face of the Monkey. This shortening was not accomplished 

 without some amelioration of the conditions in which they 

 obtained their food, which perhaps explains the thinning of 

 the hair on this almost naked face. 



Furthermore, the variety of attitudes necessarily assumed 

 by climbing animals living in trees must have prepared them 

 for the erect position that the large Apes only partially 

 succeeded in accomplishing. These various transformations 

 were early realized. In the Eocene deposits of Patagonia the 

 brothers Ameghino discovered a whole series of Primates which 

 they named Homunculus, Tetraprothomo, TriprotJwmo, and 

 Diprothomo, meaning respectively miniature man, great-great- 

 great-grandfather, great-great-grandfather, and great-grand- 

 father of man. According to them the cradle of mankind was 

 not, as de Quatrefages believed, at the foot of the great Tibetan 

 Highland, where the different human races are still found in 

 proximity, but in South America. Unfortunately, as Marcellin 

 Boule has shown in his brilliant memoir on the Chappelle-aux- 

 Saints Man, all the Ameghino Homunculi are still too far 

 removed from Man to be included anywhere in his genealogy. 



