158 



INITIATIVE IN EVOLUTION 



axis of the digits. This arrangement is observed on the remaining 

 segments of the digits except, very significantly, on the outer or 

 radial side of D 2 and the inner or ulnar side of D 5 where they slope 

 more or less towards the palm. Their lines thus cross slightly 

 those of the skin-flexures in these small areas. On the radial side 

 of D 1 this slope appears in a minor degree, but here it coincides 



Fig. 59.- 



-W. K. Right hand drawing of papillary ridges, 

 made from impressions. 



with those of the flexures. On the palm are similar arrangements 

 of the ridges near the radial and ulnar borders, and especially on the 

 two great eminences, thenar and hypothenar, also at the bases of 

 digits 2, 3, 4 and 5. Over the rest of the palm they are arranged 

 in a longitudinal or oblique direction. These brief descriptions are 

 enough to show the close correspondence of the arrangement of 

 the ridges with the flexion of the numerous joints of the hand. 

 An observer can demonstrate this by holding up the open hand in 



