38 THE BONES. 



wading tribe, which, collects its food in shallow 

 water, or moist sandy places, lias a very different 

 sort of beak, of singular construction, resembling 

 flexible flat pieces of whalebone, and not bending 

 downwards as is usually the case, but turning 

 upwards ; with this it scoops up spawn, worms, or 

 other soft water insects. One other beak only shall 

 be mentioned, namely, that of the Spoonbill, which, 

 in its food, partaking of the nature of the Heron 

 and Duck tribes, is provided accordingly; its inte- 

 rior part being furnished with rough projections, 

 which prevent the escape of such slippery things as 

 small fish, while its wide spoon-shaped end enables 

 it to crush and sift mud and weeds, for worms or 

 soft vegetable matter. 



The bones of birds, like those of animals, are for 

 the most part white, but in other respects they 

 differ materially from those of four-footed animals, 

 being composed of a thin, firm, and partly elastic 

 substance, formed in layers, apparently fastened 

 together, and almost always hollow; the cavities 

 never containing marrow, but air, and communi- 

 cating with the lungs, by considerable openings; 

 whereby they are rendered buoyant and light, to a 

 much greater degree than is generally supposed. 

 Thus a portion of the leg of a goose, about two inches 

 in length, weighed about forty grains, while a piece 

 of the leg of a rabbit (the marrow having been ex- 

 tracted, and both being perfectly dry, and as nearly as 

 possible of the same thickness and length,) weighed 

 seventy-five grains, or nearly twice the weight of 

 the similarly-sized bone of the goose ; and yet so 

 firm and strong was this latter, that, although in 



