HEPBUEisr — The Papillary Ridges on the Hands and Feet of MonJceys and Men. 535 



circumstance that they are not rolled impressions, in other words the eleva- 

 tion occupying the interspace is, probably, so large that the boundary fur- 

 rows have not been represented, and only a part of the large enclosed pattern is 

 seen. 



In comparing the lower monkey patterns with those of man the most note- 

 worthy feature is the great simplicity of the former. Practically, all the patterns 

 in my possession are modified loops, whose cores are represented by multiple rods 

 running longitudinally. These patterns occupy a much larger area proportionately 

 than in man, although some of them are suggestive of certain human impressions 

 figured by Galton. In the cliimpanzee a looped pattern is present in a distinct 

 interspace. Instances of a pattern resembling a double- spiral are seen in the 

 mandrill (PI. xlvi.) and in the black ape (PI. xlvii.), while in the orang-utan 

 interspace patterns of the nature of loops and ellipses may be seen. 



Thus, in the cliimpanzee and orang-utan we find patterns similar to those 

 commonly seen in man, whereas among lower monkeys the patterns approximate 

 more closely to those found in the palm and sole, in which regions, as already 

 explained, the shape and immediate surroundings of the eminences determine the 

 nature of the pattern assumed by the papillary ridges which cover them. 



Finally, in the higher apes and in man the jDatterns become more restricted in 

 size and complex in outline because of the more circumscribed nature of the 

 elevated area they cover, and for the same reason they are readily presented in an 

 interspace enclosed by the diverging transverse ridges, wliich, in their turn, have 

 more scope for free development. No doubt the reduction in the size of the 

 pattern-area on the terminal phalanges, which corresponds to a diminution in the 

 size of an elevation, i« directly associated with a change in the functions per- 

 formed by the terminal phalanges as compared with those of the lower monkeys. 



Conclusions. 



1. The papillary ridges and their intervening furrows are adjuncts to the pre- 

 hensile function and power of the hands and feet as well as arrangements associated 

 with increased sensibility and discrimination of the sense of touch. 



2. The eminences on which papillary ridges form designs or patterns are 

 specially developed areas raised above the general level of surrounding parts. 

 They are also special developments in relation to the prehensile function. This 

 accounts for their constancy in the hands and feet of animals which have these 

 organs modified for prehension. 



3. The " design " which covers each of these eminences has its character 

 ■determined by the position, shape, and dimensions of the particular eminence. 



