Webster 1913 Edition
[L., pl. of
The class of Vertebrata that includes the birds.
☞ Aves, or birds, have a complete double circulation, oviparous reproduction, front limbs peculiarly modified as wings; and they bear feathers. All existing birds have a horny beak, without teeth; but some Mesozoic fossil birds (Odontornithes) had conical teeth inserted in both jaws. The principal groups are:
Carinatæ, including all existing flying birds;
Ratitæ, including the ostrich and allies, the apteryx, and the extinct moas;
Odontornithes, or fossil birds with teeth.