importance to him to be masked for the eyes of the little ground beasts on whom 

 he feeds. (See Figs. 101-102.) 



Seen against snowy ground, which is common enough through a large part 

 of the eastern skunk's range, a boldly pied pattern of white and black, such 

 as he wears, is of course most potently 'ruptive.' But it does not truly oblit- 

 erate, because all the black part of the beast is left rankly conspicuous, and has 

 too peculiar a form, in such a view, to be easily ignored, or mistaken for a land- 

 scape-detail. Northern skunks, however, vary a good deal in pattern, and 

 the very whitest of them are doubtless well disguised, in certain views, against 

 snowy ground, particularly amid trees and sticks and stones and bushes 

 and other inanimate dusky details. In this case, as throughout the whole 

 great field of phenomena we are studying, it stands to reason that a special 

 development of costume must serve minor as well as major ends* But how- 

 ever potently 'ruptive' (and therefore essentially obliterative) in their effect 

 when seen against the ground the whitish patterns of skunks and skunk- 

 like beasts may sometimes be, the paramount function of these patterns is 

 certainly the picturing of sky, as our figures show (Figs. 95-103). Both 

 uses are served, perhaps almost in equal measure, but with the balance of 

 importance probably tipped somewhat toward the ground-matching function, 

 by the wholly or almost wholly white costumes of several snow-land animals. 

 Such — to begin with those least remote from the skunks — is the rare, bear- 

 like Ailuropus melanoleucus, of Thibet; such are the Arctic hares and foxes, 

 the boreal weasels and some of the boreal hares, and the Polar Bear. Almost 

 all of these, and their counterparts among boreal and Arctic birds — the ptar- 

 migans, the snow buntings, the Snowy Owl, and the White Gerfalcon — almost 

 all of them, mammals and birds alike, have a few sharp black markings in their 

 mainly immaculate white costumes. These evidently serve as what may be 

 called 'distractive' or 'fixed dazzling' marks. They are, in most cases, too 

 small to show except in a very near view — when, by their sharp but isolated 



* Or, in terms of the Natural Selection theory, that each development is the product of the sum 

 of all its uses, big and small. 



151 



