DERMATOGLYPHICS IN PRIMATES 181 



Examining first the palm, some New World monkeys (Aotus, 

 Ateles, Lagothrix and Cebus) resemble the Old World monkeys 

 in presenting a disto-proximal gradient in pattern intensity. 

 The Callithrichidae and Alonatta (with Saimiri as an inter- 

 grading form) present relationships which are like those in 

 certain prosimians, where the gradient relation is disorganized. 

 In respect to the sole, Lagothrix and Cebus are exceptions to 

 the general trend in monkeys, in which there is conformity to 

 the disto-proximal gradient. In these two genera it is the 

 intermediate group which presents maximum intensity rather 

 than the distal group. The only other exception occurs in 

 Pygathrix, which, as noted above, is in other respects a non- 

 conformist to trends in Old World monkeys. 



The New World monkeys are more asymmetrical than Old 

 World monkeys (with the exception of Pygathrix) in the 

 pattern intensities of right and left sides (table 9). The 

 platyrrhines show consistently more asymmetry of the sole 

 than of the palm, while in Old World forms there is a tendency 

 toward reversal of this relationship. In the New World 

 monkeys pattern intensity is characteristically greater in the 

 palms and soles in the right side ; in Old World monkeys there 

 is a reversal of this relationship which is consistent in the 

 palms of the four genera but inconsistent in the soles. The 

 relative asymmetry of the palm varies among the four genera 

 of New World monkeys in which the numbers available admit 

 analyses of asymmetry. Alouatta may be regarded as the most 

 primitive, both because the total asymmetry is less than that 

 in Saimiri, Ateles and Cebus, and because palm and sole are 

 about equally asymmetrical. In this feature Alouatta is in- 

 clined toward the catarrhine monkeys. 



Gibbon. Hylobates, the most extreme of all brachiators, 

 has the most specialized dermatoglyphics yet considered. The 

 elongated palm is distinguished by an almost strictly longi- 

 tudinal coursing of ridges, the character of the longitudinal 

 system being accentuated by the prevailing absence of pat- 

 terns except in the extreme proximal region. The first inter- 

 digital interval is extended far proximally, isolating from 



