PALM AND SOLE STUDIES. 



189 



more detail. In this is seen better the almost perfect condition 

 of the fourth interdigital, with its three triradii. Fig. 5 shows a 



J^ 



FIG. 4. Detail taken from Fig. 3, enlarged. Here the third interdigital pattern 

 is very typical, and compares well with the primitive hypothenar shown in Fig. 

 2. 



detail of the right palm of the author's wife (No. 70) with inter- 

 digitals III. and IV., the first with two triradii, the latter a rudi- 

 ment. In the actual hand these two areas are especially promi- 

 nent, appearing almost like minute papillae, with the patterns on 

 their apices. In the left hand of the same individual (Fig. 6) the 

 same two interdigitals are shown, but only one of them is a whorl, 

 the 1 1 Id, while the IVth is simply a loop, a very common pattern 

 in the European-American race, and almost usual enough to serve 

 as a racial characteristic in Japanese and Chinese. 



Occasionally one meets with either the third or the fourth 

 interdigital as perfect as in Figs. 3 and 4, but it is always a 

 surprise. My first experience of this kind was in one of two twin 

 girls, relatives of the Director of the Eugenics Record Office at 

 Cold Spring Harbor, L. I., but not found in her sister. This was 

 in the right hand, and showed a whorl with three triradii, in the 

 position of the Hid interdigital (Fig. 7). In enlargement (Fig. 8) 

 it shows the three triradii. Fig. 9, a sketch taken with an Abbe 

 camera, shows the details of the separate ridges. The corre- 



