THE PHYSIOLOGY OF THE SENSE OF TOUCH 147 



The foot shows on the phalanges, both arches and loops. In 

 this species then, arches and loops appear, but no whorl. 



Cebus fatuellus (Figs. 23, 24) shows an extensive development 

 of whorls on the digits, palm and sole and loops, but only one 

 group of arched ridges, on the hypothenar eminence. 



The genus Pafio (Figs. 25, 26, 27, 28) with powerful palmar 

 and plantar portions of the hand and foot and small digits 

 present numerous whorls, a few loops and no arches. 



Cynopithecus niger (Figs. 29, 30), with a better development 

 of digits than the Baboons and generally well-developed hand 

 and foot, shows numerous arches and loops on the digits, with 

 well-formed whorls on the palm and sole, similar to those of the 

 Baboons, 



The Cercopithecida^ (Figs. 31, 32, 33, 34, 35, 36, 37, 38, 39, 40) 

 examined, have increased numbers of arches and loops on the 

 phalanges, and these are also freely interspersed with whorls on 

 the palm and sole. 



The HylohatidcB (Fig. 41) show numerous arches on the digits 

 and on part of the palm, no whorls, and a few loops. This fact 

 agrees with the powerful supporting action of the hands by 

 wliich the animal swings from tree to tree, and indicates 

 simphcity of function. 



The Simia satyrus (Figs. 43, 44) has a considerable development 

 of arches on the digits of the hand and loops on the terminal 

 phalanges which accords with the fact of the great use made of 

 its long, powerful arms and active digits in its arboreal life. 

 The foot also has numerous arches as well as loops on the digits. 

 The foot and hand of the Orang differ less from one another 

 than do those of any other Anthropoid Ape. 



Gorilla (Figs. 45, 46) has a hand and foot the digits of which 

 are less relatively important than the Orang's ; and present fewer 

 loops and arches on the middle and proximal phalanges, but 

 on the terminal phalanges loops, and on the palm at the clefts 

 of the digits. The relatively small number of arches on the 

 digits is in keeping with the higher and more complicated use 

 to which the hand of the Gorilla is put, than that of the Orang. 



The Chimpanzee's hand and foot (Figs. 47, 48) have numerous 



