Page:Natural History, Birds.djvu/290

Rh eggs, resembling those of a goose. The stomach, notwithstanding its vegetable food, is but slightly muscular: the windpipe (trachea) has an abrupt bony box or enlargement about the middle, somewhat like that of the male Velvet Pochard (Oidemia fusca). The loud and piercing character of its voice is doubtless connected with this remarkable structure.

In the very valuable and elaborate observations of the late Mr. Vigors on the affinities of animals, he remarks that the Rallidæ are separated from the other Families of their Order, and united among themselves, by the shape of their body, which is compressed and flattened on the sides, in consequence of the narrowness of their sternum. "If we were allowed," continues this acute naturalist, "to draw an inference from the analogical construction of other bodies, which move with the greater facility through the water in proportion as they assume this compressed and keel-like form, we might almost conclude that this structure, peculiar to the birds of the present Family, facilitates their progress through that element, and is intended to counterbalance the deficiency in the formation of the foot, which separates them from the truer and more perfectly formed water-birds…… It is certain that the greater portion of these birds are excellent swimmers; and in such habits, as well as in the shortness of their tarsi, which is equally conducive to