162 CHARLES MIDLO AND HAROLD CUMMINS 



definitive form and undergo no change even though the 

 eminences are subsequently modified. We are, however, 

 entitled to consider the most highly developed patterns as 

 primitive in the sense that they express the maximum degree 

 of fetalization of the pads which are responsible for their 

 production. Whether the pads viewed as primitive are so 

 actually is problematic. It is merely that these fetalized pads 

 are of the form most widely present among mammals gen- 

 erally, and prevalence may not be a safe criterion of primitive- 

 ness. Furthermore, the extreme differences in dermatoglyphic 

 expressions among some human races illustrate that categories 

 of primitiveness in the dermatoglyphics of primates may be 

 vitiated by the introduction of pattern-determining factors 

 which are independent of those more directly related to a 

 phylogenetic sequence. 



The complications attending search for the primitive con- 

 figuration are exemplified in the prosimians. The several 

 genera within this one group include the total range of vari- 

 ation from the most * l primitive ' ' to the most highly specialized. 

 Galago, for example (figs. 29-32), presents consistently in 

 palm and sole whorls and whorl-like patterns. Tarsius (figs. 

 9-16), in contrast, shows almost a total suppression of pat- 

 terns, while the other genera form transitions between these 

 extremes. Likewise among both monkeys and apes, and even 

 among human races, there are grades of variation from the 

 more " primitive" to the "advanced" condition in which pat- 

 terns are less well developed and less frequent ; such variations 

 are both intergeneric and intrageneric or intraspecific. From 

 the observations assembled by Dankmeijer it is clear that 

 the marsupials likewise run the gamut of dermatoglyphic 

 expression, some forms being primitive in the sense of having 

 abundant whorls, and others possessing only open fields, while 

 some genera are even so primitive as to lack ridges. 



Such attempts to trace dermatoglyphic patterns from an 

 assumed primitive stem through steps of progressive advance 

 lead to still other uncertainties. It seems to be quite clear 

 that the presence of ridges is an advance over an epidermal 



