434 Palms and Soles 



designated by me as the accessory hypothenar, appears in members of this 

 order between the hypothenar and the 3rd palmar (or plantar) centres, 

 the homologies of which are as yet uncertain. It is much smaller than 

 the rest and may be merely a variant with but little morphological 

 significance. 



IV. In Arboreal Primates these patterns in the papillary ridges in- 

 crease the tactile function by their varied direction, a function which 

 is evidently of so great importance in an animal swinging from bough 

 to bough that they are kept to a uniform standard through natural 

 selection. 



V. In man, and probably in some of the higher Anthropoids, the 

 special phase of the tactile function furthered by this arrangement 

 becomes of reduced importance, and thus the patterns are much less 

 pronounced and are found in all stages of reduction, even to that of 

 complete loss. As in all cases of vestigial organs, there is great indi- 

 vidual variation, ranging from atavistic forms, in which several of the 

 centres appear, to those in which the papillary ridges of the entire 

 palmar and plantar surfaces run in wavy, approximately parallel lines, 

 with no suggestion of loops or other definite patterns. Corresponding 

 probably to the greater importance of the tactile function in the finger 

 tips, the five apical patterns upon the balls of the digits show a lesser 

 grade of this reduction, and, although often exhibiting reduction in the 

 complexity of the pattern, seldom become as completely obliterated as 

 in the palms and soles. 



Our knowledge of the actual epidermic markings of the human palms 

 and soles, a knowledge which is seen by the above to be of the highest 

 importance, has been advanced, more than by anyone else, by Sir Francis 

 Galton, who has published a series of investigations and observations 

 covering a period of many years. Although he has treated his subject 

 'with a minuteness of detail which leaves nothing to be desired in the 

 territory to which he has turned his attention, this territory has been 

 almost entirely limited to a single small area, that of the volar surfaces 

 of the terminal joints of the fingers, his "finger-tips." To the re- 

 mainder of the palmar surface of the hand he devotes but little atten- 

 tion (five small figures of palms marked off into areas, together with 

 three pages of text in " Finger Prints," pp. 54-56), and he dismisses 

 the subject of the sole of the foot with the following extract (Ibid., 

 p. 56) : " The ridges on the feet and toes are less complex than those 

 on the hands and digits, and are less serviceable for present purposes, 

 though equally interesting to physiologists. [Does he not mean mor-. 

 phologistsfl Having given but little attention to them myself, they 

 will not be again referred to." 



