DERMATOGLYPHICS IN PRIMATES 159 



circumstances that have negligible significance in the desired 

 comparisons. 



It may be assumed, though no relevant comparative studies 

 are available, that the same fundamental processes of de- 

 velopment are concerned in the elaboration of dermatoglyphics 

 in non-human primates. In some genera of prosimians and 

 monkeys the volar pads attain a development far greater 

 than that observed in man, persisting in the adult as prominent 

 and bluntly pointed elevations, each more or less definitely* 

 circumscribed. It is in such forms that patterns are expressed 

 more constantly than in the human palm and sole. On the 

 basis of comparing fetal pads in man, macaque and Tarsius, 

 it is evident that groups showing great unlikeness in adult 

 pad expression and in dermatoglyphics are brought into closer 

 relationship if observed in the period of maximum pad de- 

 velopment. Such accentuation of similarities in fetal stages 

 is in keeping with increasing resemblances of other features 

 among different forms in progressively earlier development. 

 Unlikenesses among the groups, with respect to dermato- 

 glyphics, are the associates of unlikenesses in the form, sub- 

 sidence, and circumscription of pads; differences in general 

 form of the hand and foot also are correlated with different 

 conditionings of ridge direction. It should be reemphasized 

 that 



* * dermatoglyphic variations are so numerous and so manifold 

 that they reveal many variables which though influenced by 

 similarly variable pad reliefs are of a magnitude far exceed- 

 ing that actually observed in the pads. It is impossible to 

 reduce the pad variables to a reliable quantitative expression, 

 and the character of the observed variables is such that they 

 must be quite different in two compared pads to be detected 

 at all." (Cummins, '29.) 



The fetal behavior of volar pads is to be taken both as a 

 reflection of phylogenetic history and as an ontogenetic antici- 

 pation of definitive volar reliefs, which have a functional 

 relationship with varying uses of the members. The differ- 

 ences in use of the anterior and posterior members in the 

 same animal, together with the varying habits of different 



