DERMATOGLYPHICS IN PRIMATES 125 



of the comparison (table 3). The dimensional relationship in 

 question is the intermembral index. We have made immediate 

 uses of the intermembral index based upon total lengths of 

 the extremities, though the indices involving humerus plus 

 radius and femur plus tibia (Schultz, '30 and '37 a) are found 

 to agree with the seriations of the higher primates now to be 

 presented in terms of total lengths of the extremities. Since 

 the intermembral index of extremity length diminishes in 

 prenatal and postnatal development, it seemed most promising 

 to inspect the indices which obtain at about the time of 

 differentiation of the dermatoglyphics. The figures extracted 

 from Schultz apply to fetuses corresponding to human gesta- 

 tion within the period comprising lunar months 4-6 inclusive ; 

 however, the seriations of the higher primates retain the same 

 order, regardless of whether the intermembral indices are 

 those of the fetal period or later. It will be noted (table 3) 

 that all the higher primates gibbon, the three great apes 

 and man - are arranged in the same sequence, whether 

 ordered according to the intermembral indices of total in- 

 tensity or of dimensions. As for 'the other genera represented 

 in the table, there is a less consistent seriation, and Cebus is 

 the most conspicuous non-conformist in this series, having 

 next to the highest pattern-intensity index of the nine genera 

 and next to the lowest index of extremity lengths. The ex- 

 planation of these discrepancies, which are in such contrast to 

 the orderly behavior of the five genera of higher primates, 

 can hardly be explained away on the assumption of a technical 

 discrepancy, though it may be noted that the index of extremity 

 lengths in Cebus is based on a single specimen, and that some 

 fluctuation among individuals might be expected. Table 10 

 in Schultz ('26) lists the intermembral indices of extremity 

 lengths in six age groups, three of them of the fetal period, 

 and three groups of postnatal specimens, infant, juvenile and 

 adult. While the general tendency of the index is to diminish 

 with development, the progression, at least as indicated in 

 those genera with larger number of specimens, is not uniform, 

 the lack of uniformity being presumably associated with 

 individual differences. 



