114 CHARLES MIDLO AND HAROLD CUMMINS 



the area through which these alignments may be traced. The 

 nearly consistent combination of longitudinally coursing 

 ridges in the central palm and transversely coursing ridges 

 bordering the interdigital patterns may be regarded as a cor- 

 relate of the extent and distribution of the pads which are 

 so highly developed in this group. 



The soles in Old World monkeys are quite variable among 

 the genera with respect to ridge direction. At the one extreme 

 the ridges may be transverse (as in Papio) and at the other 

 longitudinal (as in Colobinae) ; intermediate slants are not 

 uncommon either as a characteristic of an entire sole 

 (Pithecus, Lasiopyga) or in combination with an area of 

 longitudinal ridge direction in the same sole. Different soles 

 of the same genus may show unlikenesses in general ridge 

 direction. 



In the Hylobatidae ridge courses of the palm are strictly 

 longitudinal, and in the sole either longitudinal or slanted. 

 The same description applies to Pongidae except that in Pan 

 the palmar ridge courses may be either longitudinal or 

 oblique. The characteristic ridge direction in the human 

 palm is a combination of longitudinal and diagonal, while in 

 the foot the configuration is transverse or on a slant closely 

 approaching it. 



CAUDAL DERMATOGLYPHICS 



Of the monkeys possessing prehensile tails, confined to the 

 New World group, there are three genera in which caudal 

 dermatoglyphics occur. Wood Jones' ('29) description of 

 Lagothrix would apply equally well to the tails of Alouatta 

 and Ateles : ' ' The tail is long, highly specialized as a pre- 

 hensile organ and naked below on its terminal part. This 

 naked portion of the tail is beset with papillary ridges 

 extraordinarily like those upon the palmar surface of a 

 human finger. ' ' 



In Alouatta (five specimens) the ventral surface of the 

 tail presents two series of ridges meeting at the midline to 

 form a simple herringbone configuration; the ridges in each 



