DEBMATOGLYPHICS IN PRIMATES 145 



tion to digits II and III, to approximation and suppression of 

 these digital triradii. This tendency is an abortive expression 

 of syndactyly (Cummins and Sicomo, '23; Ford, Brown and 

 McCreary, '41, p. 52). The comparable manifestation in the 

 palm is less frequent, but when it occurs the involvement is 

 usually related to digits III and IV; even in the absence of 

 such marked approximation or obliteration of digital triradii, 

 measurements have shown that the tendency is nevertheless 

 present (Cummins, Leche and McClure). 



In the absence of measurements of ridge breadth on the 

 toe tips and sole it is impossible to draw comparisons of vari- 

 ations in ridge breadth with respect to the anatomical axes 

 of the two members ; yet the observations of ridge breadth in 

 the hand (Cummins, Waits, and McQuitty) yield suggestive 

 indications of regional variations at least partially under 

 apparent regulation by factors associated with the anatomical 

 axis. On the finger tips, for example, ridges are finer ulnar- 

 wards from the axis than they are in the digits radialwards 

 from it. In the distal palm the finest ridges are in the 

 anatomical axis. It is to be hoped that similar measurements 

 of the sole may be made available for comparison. 



BILATERAL ASYMMETRY 



The occurrence in man of unlike pattern frequencies in right 

 and left hands is recognized. Studies in diverse racial popula- 

 tions have demonstrated in right hands, among other bi- 

 manually different trends : a higher frequency of whorls 

 on the finger tips (Bonnevie, '24, and others) ; more abundant 

 patterns in the hypothenar, second and third interdigital 

 areas; and a lesser frequency of patterns in the thenar/first 

 interdigital and fourth interdigital areas ( Cummins, Leche 

 and McClure; H. H. Newman, '30). There are indications 

 that some of the trends of bimanual difference are altered 

 in the left-handed (Keith; Bettman, '32; Leche, '33; H. H. 

 Newman, '34; Cummins, '40; Rife, '41). Though the specific 

 dermatoglyphic trends associated with functional dominance 

 of one or the other hand are not yet fully established, the; 



