

DISTINGUISHING IDENTICAL AND FRATERNAL TWINS 



4i3 



give very briefly a general summary of the 

 main results. 



My study has revealed that the finger, 

 palm and sole prints of the twins whose 

 monozygosity is evident on various grounds, 

 such as thesimilarity of physiognomy, body 

 build and school standing, resemble each 



The similarity of the pairs of mono- 

 zygotic twins is especially marked between 

 the fingers, palms or soles of the same 

 side (right or left), so that very often the 

 hands or feet of the same side of different 

 individuals resemble each other more 

 closely than the two hands or feet of the 

 same individual. To represent in symbols, 

 let r and / stand respectively for the right 

 and left hand or foot of the one twin A, 



Fig. i. Monozygotic (?) Girl-twins, prom Mr. 



Obonai's Collection of Photographs 



of Twins 



Fig. 3. Boy-girl Twins very Different in Body 



Build; Children of a Primary School 



of Kyoto 



•other closely, much more than the prints 

 of the different-sex twins or of the same- 

 sex twins who are identified as dizygotic. 

 To give a rough idea of the contrast of the 

 two kinds of twins, the finger prints of the 

 monozygotic twins very seldom show 

 differences in the type of pattern (whorl, 

 twin loop, double loop, ulnar loop, etc.) 

 in more than two pairs of corresponding 

 fingers, whereas in dizygotic twins the 

 •difference is met with usually in more 

 than two pairs of corresponding fingers. 



and r' and /' respectively for A', the 

 identical twin of A, then 



r — r' (or /—/')< r — I (or r' — /') 



Such a condition, so far as I have ascer- 

 tained, is met with in no case of different- 

 sex twins nor of same-sex twins whose 

 dizygosity is undisputed. So that this 

 may serve as a criterion for identifying 

 many monozygotic twins. 



To my mind, the difference in pattern of 

 the two hands or feet of the same indi- 





