126 THE GENERAL ANATOMY OF THE CERCOPITHECIDAE [SECT. A 



developed, but have experienced a slight displacement laterally, 

 so that they appear to be thrust towards the tibial side of their 

 original positions. The first interdigital pad is continuous with 

 an elongated eminence, extending nearly to the heel (and possibly 

 equivalent to a proximal thenar pad). The fourth interdigital 

 pad is closely connected or even continuous with a similar but 

 narrower " fibular " eminence reaching the heel (and, in part, 

 representative of the proxi- 

 mal anti-thenar pad of the 

 primitive ground-form). 



The apical pads of the 

 digits bear patterns described 

 as elliptical loops. On the 

 thumb (pollex)in particular, 

 the appearances strongly 

 suggest the presence of 

 the entwined loops called 

 (by Schlaginhaufen) " vortex 

 duplicatus." On the middle 

 phalanges, the ridges run 

 transversely or in flattened 

 arches. They are less nu- 

 merous here, and in Macacus 

 cynomolgus they may even 

 fail to develop in this part. 

 On the proximal phalanges, 

 ridges with an oblique 

 direction mark the pollex, 

 arches or loops replacing 

 them in the remaining 

 digits. On the interdigital 

 pads, the general tendency 



is to the appearance of " vortices duplicati" on the summit, while 

 the spaces between the pads are marked by a series of curved lines. 

 These originate in the "carpal" region, and radiating thence, they 

 spread out towards the margins as they descend. 



The general disposition of the papillary ridges on the plantar 

 surface (Figs. 77, 78) resembles that just described as characteristic 



Fig. 77. Macacus nemestrinus. Cutaneous 

 grooves of the sole of the foot. (From 

 Schlaginhaufen.) 



