112 CHARLES MIDLO AND HAROLD CUMMINS 



Th p and TV are frequent in the soles of some New World 

 monkeys, though it may be recalled that fusion between them 

 is common. (4) Fusion between Th d and I in the sole occurs 

 occasionally, but with no approach to the regularity with 

 which such fusions occur in the palm, especially in the catar- 

 rhines. (5) Fusions between interdigital configurational fields 

 are more common in the sole than in the palm. Such fusions 

 are distributed among diverse groups, though occurring in- 

 frequently except in higher primates; in the palm they are 

 confined to the higher primates. 



Comparisons among groups of primates. Difficulties arise 

 in the endeavor to convert the evidences of deviation from 

 the basic plan into quantitative terms; additionally, the 

 numbers available in some genera are too small to provide 

 for a fully satisfactory analysis. There may be made, not- 

 withstanding, certain general statements which apply to the 

 main border pads, seven in the palm, eight in the sole. The 

 prosimian genera are widely variable with respect to the 

 extent of deviation from the plan. Nycticebus, Perodicticus, 

 Galago and Lemur present the least departures, while Tarsius 

 shows much more modification, especially in the foot. In this 

 as in other analyses the prosimian genera are shown to be 

 heterogeneous. Setting the group aside because of such 

 peculiarities, the order of increasing tendencies to deviate 

 from the plan is : New World monkeys, Old World monkeys, 

 higher primates. For the higher primates the following order 

 of modification is resolved : Homo <Pongo< Gorilla < ?Pan< 

 Hylobatidae. 



GENERAL RIDGE COURSES 



The next descriptive analysis involves consideration of the 

 prevailing directions of ridges over the palm and sole, apart 

 from the localized irregularities of areas which are patterned. 

 In forms having very expanded patterns, for example Papio 

 (figs. 237-260), the determination of prevailing ridge direc- 

 tions is complicated by the fact that the areas free from 

 patterns are not only small, but probably influenced by their 



