carinatæ

from The Century Dictionary.

• One of two prime divisions of birds instituted by Merrem in 1813; his Aves carinatæ, including all birds then known to have a carinate sternum, as opposed to Aves ratitæ, or “flat-breasted” birds, consisting of the struthious or ratite birds.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural A grand division of birds, including all existing flying birds; -- So called from the carina or keel on the breastbone.