monocondyla

from The Century Dictionary.

• noun The Reptilia and Aves (reptiles and birds) collectively: so called from the single occipital condyle characteristic of these classes among the higher vertebrates. The term indicates a group exactly conterminous with Sauropsida. Opposed to Amphicondyla.

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

• noun plural (Zoöl.) A group of vertebrates, including the birds and reptiles, or those that have only one occipital condyle; the Sauropsida.