NO. 10 HUMAN' HAIR AND PRIMATK PATTKRNING MILLER 3 



The making of patterns appears to be a process quite distinct from 

 that by which a general harmonizing of animals with their natural 

 surroundings has been effected. Nearly allied, pallid, desert species, 

 for instance, may be distinguished from each other by details of indi 

 vidual pattern as obvious as those that serve to mark richly colored 

 species living in humid forests. General types of color and surface 

 may have their relations to the surroundings in which animals pass 

 their existence; but the special patterns of the species that conform 

 to any one type cannot be shown to have such relations. It may be 

 plausibly argued that the blotched and spotted color schemes of 

 arboreal warblers and the streaked color schemes of grass-living 

 finches have something to do with the unlike surroundings in which 

 warblers and finches pass their lives. But this argument would not 

 apply to the dift'erences between the patterns of Blackburnian and 

 black-throated green warblers nesting together among the same ever- 

 greens, nor to those between savannah and grasshopper sparrows 

 living in one meadow. Still less would it be possible to explain, on 

 grounds of special needs, why species of horned-toad differ from 

 each other in the number and form of the spiny outgrowths on the 

 head, or why one species of gnu has a fringe on the brisket and 

 another has not. Patterning, therefore, seems to be something physio- 

 logically inherent in animals rather than something that the environ- 

 ment has imposed upon theuL 



PATTERNING IN PRIMATES 



Though patterning occurs in all groups of mammals — even in 

 rhinoceros, hippopotamus, elephant, and cetacean — it is among the 

 primates that the tendency attains its greatest development. In no 

 other group does it make such full use of its chief materials, namely, 

 the color of the skin, the color of the hair, and the contrasts that 

 can be obtained from dift'erences in quality and length of hair. No 

 l)etter example of this process could be given than the one furnished 

 by the head markings of monkeys grouped on Plate i. The animals 

 there represented are nearly related species that live under essentially 

 uniform surroundings in the great African forest belt. No two of them 

 have the same arrangement of dark and light areas on the head ; three 

 liave conspicuous white stripes over the eye ; one has a black stripe in 

 the same place ; in five the cheeks are white, while in three they are not 

 white ; one (fig. 2) is bearded, while seven are not ; one (fig. 4) has a 

 moustachelike mark of white in the skin of the upper lip ; another 

 has a boldly contrasted spot of fine white hairs on the nose. Other 

 patterns in priiuates come from lengthening, shortening, and \arying 



