396 



HARRIS H. WILDER. 



Referring again to any of these diagrams, it will be seen that 

 the pattern in its typical form is centered upon about the middle 

 of the hypothenar region of the hand, and that its three triradii 

 consist typically of (a), an inner upper, (c), an inner lower, and 

 (b), an outer, the first situated near the hollow in the center of 

 the palm, the second down upon the wrist near its middle line, 

 and the third far around upon the outside edge of the hand. 

 This last is, indeed, frequently placed so far around the hand as 

 to be extralimital, that is, placed beyond the limits of the true 

 friction-skin, and indicated only by the convergence of the fric- 

 tion ridges along the transition zone between friction-skin and the 

 normal skin of the back of the hand. 



FIG. 3 



FIG. 4 



FIG. 3. A typical hypothenar, based on Fig. 2, an actual print. 



FIG. 4. A hypothenar pattern, in which triradius a is wanting, and the ridges 



escape in that direction. This is type A. 



It is now possible to imagine any one of these three triradii 

 degenerating, and this degeneracy going so far as to allow the 

 escape of the ridges that are normally held in place by its two 

 embracing radiants. Such a loss would convert the concentric 

 circles, a WHORL pattern, into a typical LOOP pattern, open to the 

 point from which the given triradius has disappeared; and as 

 these three triradii are designated as a, b, and c, (Fig. 3) the three 

 resulting loops may receive their names from the triradius that 

 has broken down in each case, and we have types A, B, and C. 



In type A (Fig. 4) triradius a is wanting, while b and c persist, 



