154 CHARLES MIDLO AND HAROLD CUMMINS 



it to the percentage of the combined total intensities of palm 

 and sole. 



Relative asymmetry of the palm is the relationship of total 

 bimanual asymmetry to total bipedal asymmetry (obtained 

 from the membral asymmetries listed in table 9). The sum 

 of the right and left asymmetries of the palm is divided by 

 the corresponding sum of the sole, the result being expressed 

 as a proportion. Unity would indicate equality of asym- 

 metries of the hand and foot. 



The least total asymmetry occurs in the Old World monkeys, 

 though in this group Pygathrix represents an exceptionally 

 high asymmetry which is comparable to that of New World 

 monkeys. In the higher primates asymmetry is greater than 

 in monkeys : monkeys < Pongo = Homo < Pan Hylobates < 

 Gorilla. These statements are based upon the percentage of 

 total asymmetry rather than with the use of the index of 

 asymmetry. The index is of less significance for such com- 

 parison, embodying the total intensities of right and left palms 

 and soles without regard to directions and amount of asym- 

 metry of individual regions. In spite of cancellation effects 

 which are inherent in the index, Old World monkeys retain 

 their position as the least asymmetrical forms, with Pygathrix 

 again as an exception. The New World monkeys and man are 

 next in order of increasing asymmetry, but Cebus presents 

 a higher asymmetry which equals that of the great apes. 

 Hylobates exhibits the maximum asymmetry on the basis of 

 the index. 



The relative asymmetry of the palm is of particular interest. 

 In monkeys palmar asymmetry does not even approach the 

 magnitude of asymmetry of the sole, with the single exception 

 of Alouatta. The higher primates form a noteworthy sequence 

 of increasing relative asymmetry. In Hylobates asymmetry 

 of the palm is just about one third that of the sole; Pongo, 

 Gorilla, Pan and Homo are ranged in a regular progression 

 of increasing relative asymmetry of the palm (the figures 

 approximating an orderly increase through the higher pri- 



