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266 but does not reach the basisphenoid. The jugals, squamosals, and tabulars may be more or less vestigial, and even the quadrate may be secondarily fixed and immovable.

Terrestrial, burrowing, subaquatic, or subvolant. A slender epipterygoid articulates with parietal and pterygoid; no descending plates of the parietals. Palate with large openings, usually with teeth on palatines or pterygoids or both. Feet when present usually pentedactyl, with the primitive phalangeal formula, the fifth metatarsal more or less hook-shaped proximally. Eight cervical vertebrae.

. Vertebrae amphicoelous, notochordal, with persistent intercentra. Quadrupedal. Jugal vestigial. No temporal arcade. Parietals paired. Clavicles perforated near mesial end.

A family of small lizards widely scattered over the earth, comprising nearly three hundred species and about fifty genera. They are of interest because of the persistently primitive condition of the vertebrae. They must have had a long independent history from early Mesozoic times, but no species are known as fossils.

. Small lizards, from two to four inches in length, of doubtful position; referred to the Anguinidae by Boulenger. Head relatively large and broad, orbits very large, the temporal openings said to be closed. Structure poorly known, twenty-three presacrals.

Upper Jurassic. Euposaurus Lortet, France.

. Temporal and postorbital arches complete. A parietal foramen. No dermal ossicles [on back]. Teeth acrodont. Quadrupedal.

This exclusively Old-World family includes about two hundred known species of about thirty genera, some of them attaining a length of three feet. Perhaps the most noted members are the Flying Dragons (Draco), small lizards with an extraordinary development of the ribs to support a parachute membrane. Chlamydosaurus, one of the largest of the family, has an extraordinary frill about the neck