394 HARRIS H. WILDER. 



encloses and defines the pattern areas, upon which the definite 

 patterns are developed. These latter, in typical cases, form in a 

 definite relation to the original conical mound, and develop in 

 concentric circles about the apex of the cone, with the center, 

 or "core," of the pattern exactly coincident with this apex. 



When, in the Primates, the height of these structures, that is, 

 folds and mounds, becomes reduced to a flat surface, the relief 

 becomes transformed into a picture, and the mound, with its 

 enwrapping folds, becomes distinctly traceable in the ridges, the 

 pattern area covered with concentric circles, and the outer 

 contour interrupted by triradii. Two radiants of each triradius, 

 extend in nearly opposite directions and embrace, or frame in, a 

 part of the perimeter of the pattern, while a third, the divergent 

 radiant, passes off centrifugally from the pattern. 



Those patterns which are located upon the surface of the palms 

 or soles, have each three of these embracing triradii, save the 

 Third of the Interdigital series of the hand, which has four, but 

 the apical patterns, doubtless because of the rounded terminations 

 of the ends of the digits, are furnished with two only, the lateral 

 ones, while the ridges which terminate the digits continue to 

 follow around the contour of the digit, and dispense with a third 

 triradius. 



The arrangement of each pattern and its surroundings, in- 

 cluding the number of triradii originally embracing each pattern, 

 and their relative position, may be seen by a diagram, published 

 several times, to which the reader is referred. 1 Aside from this 

 the conditions seen in generalized quadrupedal mammals, as 

 shown in the 1904 paper of Miss Whipple, 2 and from which this 

 key diagram was deduced, is of fundamental interest. See es- 

 pecially the paws of Microtus, pp. 270 and 272, that of Crocidura 

 on p. 280, and the generalized diagram of this author on p. 275, 

 in which each radiant of each triradius is named. 



To select a good typical pattern, the transformations of which 

 could be conveniently studied, we may propose the kypothenar 

 of the hand (Fig. 2) for the following distinct advantages: 



i. It is a pattern with three typical triradii, and consequently 

 three divergents. It is thus better than any finger-print. 



1 "Palm and Sole Studies," BIOL. BULL.. Feb., 1916, Figs. 3-5, p. 142-144. 

 * Zeitschr.f. Morph. u. Anthrop., Bd. VII., 1904. 



