THE NATATOKES. 211 



The whole order of Natatores swim and dive without saturation, 

 their plumage being anointed by an oily liquid furnished by 

 certain glands in their skin, which renders them impervious to 

 moisture. This immunity from the effect of water is further 

 assisted by the disposition and structure of their feathers, which, 

 being smooth and three-cornered, with the barbules closely inter- 

 laced, cause the water to glide off their polished surface ; while 

 the down beneath the feathers of which we have spoken protects 

 their bodies from the cold, maintaining their natural heat, and 

 enabling them to resist the cold of the most rigorous winter. 



The Natatores are numerous both in species and individuals, 

 having their habitat in all countries. According to Prince Charles 

 Bonaparte, one of the most eminent of European naturalists, those 

 which frequent the sea-shore alone constitute one-fourteenth part 

 of all the birds on the globe, and the number of species he reckons 

 at nine thousand four hundred. They feed on vegetables, insects, 

 mollusks, and fishes. They seek the coast in the breeding season, 

 where they build their nests on the sand, or in nooks and crannies 

 of the rocks, or on the margin of lakes and rivers. 



In the spring the sea-birds assemble in large flocks, pair off, and 

 proceed to deposit their eggs in nests constructed generally with- 

 out skill, but always lined or carpeted with a fine down, which forms 

 a soft warm bed for the embryo progeny. Certain localities are 

 frequented by preference, which are occupied by innumerable flocks 

 in the breeding season, all of which seem to live together in per- 

 fect harmony. Some of the families of the Natatores are valuable 

 additions to the poultry-yard. Ducks and Geese furnish delicate 

 and nourishing food for man ; the Swan is gracefully ornamental 

 on our lakes and ponds. The down of all the aquatic birds 

 is of immense value to the commerce of northern countries. 

 The eggs are good to eat, and in many countries the inhabitants 

 consume them in great quantities. Nor does their usefulness 

 end here. Guano, so eagerly sought for by the farmer, is the 

 excrement of aquatic fowls the accumulation of ages, until, 

 in the South Pacific Ocean, it has formed whole islands, some 

 of them being covered with this valuable agricultural assistant 

 to the depth of ninety or a hundred yards. Nor is this so 

 marvellous, if it is considered that twenty-five or thirty thousand 



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