154 MOSTLY MAMMALS 
is of the concentric type (as shown in fig. A), in which 
the central ridges are longitudinal and the external ones 
form broad ellipses. In the chimpanzee, however, and 
probably also in some or all of the other manlike apes, the 
pattern on the balls of the fingers is of the form known as 
the looped type, which is of common occurrence in the 
fingers of the human hand. On the finger-tips of man 
alone occurs the still more complicated whorled type; and it 
is thus evident that even in such a minute detail as the 
arrangement of the lines on the fingers the manlike apes 
and man stand apart from their kindred, and that in man 
alone is the most complicated type ever developed, although 
even in him it is comparatively rare. 
