Aves

Definition and stakes

Portrait of Spencer Fullerton Baird Spencer Fullerton Baird,  A History of North American Birds…

“ The class of Birds (Aves) , as represented in the present age of the world, is composed of very many species, closely related among themselves and distinguished by numerous characters common to all. For the purposes of the present work it is hardly necessary to attempt the definition of what constitutes a bird, the veriest tyro being able to decide as to the fact in regard to any North American animal. ”
Source: Gutenberg

Portrait of Mrs. Loudon Mrs. Loudon,  Mrs. Loudon's Entertaining Naturalist

“ Section III.—Aquatic Mammalia, having no Hind Limbs, and the Fore Limbs converted into Fins.
XI. Cetacea, or sea mammalia, the principal of which are the whale family, the dolphin family, the manati, the porpoise family, and the narwhal, or sea-unicorn.
THE AVES, OR BIRDS, Lay eggs from which their young are hatched by what is called incubation. Their skins are covered with feathers; and their jaws are horny, without teeth. Their blood is warm, and circulates like that of the mammalia. The six orders of Aves are as follow:—
1.
”
Source: Gutenberg

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