DEKMATOGLYPHICS IN PRIMATES 183 



genera; it is difficult to establish the relative positions of 

 Gorilla and Pan in a scale of increasing modification of the 

 plan. 



By combining the pattern intensities of palms and soles, 

 and considering that decreasing pattern intensity is an evi- 

 dence of specialization, the order from the more primitive 

 to the more advanced is Gorilla, Pongo, Pan, Homo. Consider- 

 ing the hand separately, the series is Pongo, Gorilla, Pan, 

 Homo, while the order of the foot is different : Gorilla = 

 Homo, Pan, Pongo. It is evident, therefore, that palm and 

 sole have proceeded differently in the course of involution 

 of pattern intensity, and that the soles of Gorilla and Homo, 

 the two primarily terrestrial genera, retain a larger measure 

 of primitiveness. In Pongo and Homo the palm shows a 

 significant deviation from the pattern intensity of the sole. 

 In man the plantar pattern intensity is over twice that of the 

 palm; in Gorilla and Pan the plantar and palmar intensities 

 are essentially equal, contrasting with conditions in Pongo 

 where the palmar intensity is 70% greater than that of the 

 sole. Special emphasis is due this relationship of palm and 

 sole in Pongo, the only great ape presenting a significantly 

 smaller pattern intensity in the sole. In its conformation the 

 foot of Pongo is more hand-like than the foot of any of the 

 simians, and it is possible that the foot serves to a larger 

 extent in prehension. At any rate, the sole in Pongo has less 

 significance as a contact surface in walking since the animal 

 walks on the outer borders of the feet. 



The soles of Gorilla and Pan show negligible difference in 

 the pattern intensities of the thenar and hypothenar groups 

 of configurational zones, while Pongo and Homo evidence a 

 much greater intensity in the thenar than in the hypothenar 

 group. These group intensities behave quite differently in the 

 palm; Pongo and Pan show but little difference in the in- 

 tensities of the two groups, the excess being in the thenar. 

 Gorilla and Homo present marked pattern intensity differ- 

 ences in the two configurational groups, and here it is the 

 hypothenar group which bears the larger intensity. In all 



