THE LIMITS (3F HEREDITY 



183 



twins is given in the Journal of Heredity, November, 

 1 91 6 (see Figs. 30, 31). The patterns are ahke in 

 these two men, except that the thumb of the left hand 

 has a loop in one twin and a whorl in the other, while 

 the middle finger in the former has an arch, and in the 

 latter a loop. Moreover, in each twin the patterns 

 on the fingers of the left hand are in nearly every case 

 mirror-images of the patterns on the corresponding 



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Fig. 31. — Finger Prints of the Twins in Fig. 30. 



The thumbs of their left hands and the middle fingers of their 

 right hands are clearly distinguishable in pattern. 



fingers of the right hand. Another evidence that 

 these friction-skin patterns are on the borders of 

 hereditary control is found in the fact that in a 

 congenitally split finger observed b}' Wilder the 

 patterns of the two finger tips were not identical. In 

 all hands the minutiae of the ridges, such as forkings, 

 interruptions, and isolations, remain constant through- 

 out life, and these form the basis for the identification 



