DERMATOGLYPHICS IN PRIMATES 113 



conjunction with the pattern fields. The relationships are 

 quite different in a form such as Hylobates (figs. 459-533), 

 where with suppression of pattern development the ridges 

 pursue consistent courses over large areas. 



In spite of the difficulties which are introduced in many 

 genera by the expanse of patterns, it is desirable that com- 

 parisons of general ridge courses be made. As an illustration 

 of significances which may be attached to these general courses 

 of ridges, reference may be made to the long recognized fact 

 that in man the palmar ridge directions approach the trans- 

 verse more closely in right hands than in lefts. In further 

 illustration it may be mentioned that chimpanzee palms, not- 

 withstanding their sharp differences in ridge direction as 

 compared to man, display exactly the same tendency of dis- 

 tinction between right and left (Cummins and Spragg). In 

 the present material an analysis so exacting as that carried out 

 in man and chimpanzee is impossible. The following comments 

 therefore are devoted to a much more general comparison 

 of the trait among the main groups of primates. 



In some prosimians the lack of complete ridge formation 

 over the palm and sole precludes a determination of ridge 

 courses. In the prosimian genera in which ridge directions 

 can be interpreted the general course in the palm is longi- 

 tudinal, while in the sole the courses are either longitudinal 

 or but slightly slanted. 



In New World monkeys the characteristic ridge direction, 

 as previously observed by Schlaginhaufen in the sole alone, 

 is longitudinal both in palm and sole. The exceptions (palms 

 of Ateles, Lagothrix and Cebus) take the form of an area 

 of transversely coursing ridges lying proximal to the inter- 

 digital patterns, and (as in soles of Cebus) of obliquely trans- 

 verse ridges in the distal and proximal regions (the fibulo- 

 proximal coursing of Schlaginhaufen). 



It is especially interesting to note that the exceptional state 

 just mentioned in the palms of three New World monkeys 

 represents the characteristic alignment in the palms of Old 

 World monkeys, where the expansiveness of patterns restricts 



