tions, its contour will be 'broken up' against both light and dark — light 

 failing to show against light, dark against dark. Such is apparently the basal 

 and predominant use of almost all the bolder patterns in animals' costumes. 

 Often such bolder markings play a part in subtler schemes of picture-pattern; 

 but, on the other hand, they sometimes work independently of obliterative 

 shading. 'Secant' patterns, however, are almost always in its service, even 

 when they have some share of independent effect. A good example is the 

 longitudinal light-colored stripe on the scapulars or wing feathers, so very 

 prevalent among obliteratively colored birds — ^particularly those with highly 

 developed picture-patterns. It is found in its perfection on certain sparrows 

 and many gallinaceous birds. In almost every case it clearly pictures a 

 horizontal stick or grass-blade, with its shadow under it; but, picture or no 

 picture, it tends to cut the aspect of the bird in two. This marking 'is found 

 also on certain kinds of wood frog, and on toads. (See Chapter XXIV.) 

 There are also vertically 'secant' markings, e. g., the white or black-and 

 white breast-bands of some teals (Nettion), and of the Wood Duck (Aix), 

 both mentioned in an earlier chapter. 'Ruptive' markings, in general, are 

 bold, massed patterns of contrasting shades and colors, disposed at seeming 

 haphazard over the animal's body, but in reality arranged according to the 

 rigid laws of disguise. Among birds thus marked, some of the best examples 

 are sea fowl. Eider Ducks, for instance. Male Eiders, with their big, con- 

 trasting patches of black and white and buff and green — or grayish blue — 

 are doubtless very inconspicuous in deep ocean water among ice cakes; while 

 their brown, grass-patterned mates are well fitted for the task of brooding 

 their eggs on the dry shore. The non-counter-shaded male Harlequin Duck 

 (Histrionicus histrionicus), likewise, is in aspect cut to pieces by its queer, 

 black-rimmed white markings, which look like floating bits of ice, or patches 

 of snow on rocky shores. Many other sea ducks wear kindred markings, 

 and so do many land birds and even quadrupeds and other animals. The 

 more crudely-blotched black and white patterns of certain woodpeckers, the 

 black caps and white cheeks of nuthatches, and the various bold head-markings 



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