100 CHARLES MIDLO AND HAROLD CUMMINS 



Palm. In general, interdigital pads II, III and IV are the 

 least subject to aberrancies. They are individually recog- 

 nizable throughout the scale of primates, though markedly 

 lowered in Ateles, Hylobatidae, great apes and man. 



Interdigital pad I is frequently blended with the thenar 

 pad to form a single prominent elevation, as described below. 

 Pad I is separate in Tarsius, Lemur, Callithrichidae, Alouatta, 

 Aotus and Ateles. 



As just noted, the thenar pad and I are infrequently sepa- 

 rate. Except in the genera named above, the two pads are 

 fused, either lowered and melted together in one flattened ex- 

 panse (the higher primates) or joined in a single prominent 

 elevation (all prosimians except Tarsius and Lemur, all platyr- 

 rhines except Callithrichidae, Alouatta, Aotus and Ateles, and 

 all catarrhine monkeys). When there is but one prominently 

 elevated pad representing both these elements its summit 

 usually is centered in I, the region of Th forming the extended 

 proximal slope of the pad. 



Hypothenar pads also are variable. There is a single 

 elevation, H, in prosimians with the exception of Lemur, and 

 in Saimiri. In all monkeys except Saimiri and in Hylobatidae 

 there is a distinction between the two elements,. H d and H p . 

 H p is generally prominent, while the H d area is much lower 

 or even markedly flattened. In this relationship H d and H p 

 may be considered fused, with H p in the ascendancy; the 

 anatomical direction of ascendancy is the reverse of that in 

 fusions of Th and I. In great apes and man the hypothenar 

 pads participate in the flattening which is characteristic of 

 other pads in these higher primates. Still, there are slight 

 indications furnished by the hypothenar reliefs, even in their 

 reduced state, reflecting superiority of H p over H d . These 

 bare suggestions have greater significance when they are 

 considered in company with the dermatoglyphics, which un- 

 questionably evidence that tendency. 



Sole. The greatest relative prominence and distinctness of 

 pads II, III and IV occurs in prosimians. Catarrhine monkeys 

 are characterized by well developed pads in this distal border 



