especially thdse with narrowly slit pupils, are often very inconspicuous, in 

 themselves. The green and yellow eyes of many felines, especially when they 

 are surrounded by irregular fur-patterns of about the same shade, are insid- 

 iously unapparent and elusive, 'merging' well with leaves and foHage-vis- 

 tas, etc. This obliterative coloration of cats' and other predatory creatures' 

 very eyeballs must be a great aid to them in their stealthy stalking of their 

 prey. An eye like that of the Copperhead Snake (Chapter XXIV, Plate XI), 

 with its narrowly slit pupil, is as well concealed as any part of the creature's 

 obliteratively colored body. 



One more subject which must have a place in this rather miscellaneous 

 chapter is the coloration of birds in downy nestling plumage. Passerine 

 birds — most of them at least — are born naked and absolutely helpless, re- 

 maining in this condition for days. But they are almost always domiciled in 

 substantial nests, which in their turn are usually hidden amidst foliage, so 

 that the youngsters are well shielded from their foes. Such birds have no 

 true downy plumage, but pass from nakedness into a coat of frowzy contour- 

 feathers, marked somewhat differently from those of their parents, though 

 often much resembling them. But there is a great group of birds, including 

 most of the members of most of the orders outside of Passeres, whose young 

 are born with a full downy covering, which they retain for many days. Such 

 are the grebes, ducks, geese, gulls, terns, rails, shore birds, Gallina (grouse, 

 etc.), goatsuckers, hawks, owls, etc. Of these the terrestrial (and aquatic) 

 forms concern us most, for they are more exposed to danger, and have more 

 highly developed protective coloration, in the infant state, than the nesters in 

 trees. The terrestrial (and aquatic) assemblage may be again divided into 

 two sections, one including the species whose young are for a time sedentary 

 and helpless, and the other those whose young are active and alert from the 

 moment of birth, and leave the nest almost at once. Of the active sort are 

 grebes, ducks, rails, sandpipers, and all tne gallinaceous birds; while goat- 

 suckers, and, to some extent, gulls and terns, belong to the sedentary type. 

 Young grouse and other Gallince acquire the power of flight, along with con- 



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