266 THE OSTEOLOGY OF THE REPTILES 



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. 



Tribe Kionocrania 



Terrestrial, burrowing, subaquatic, or subvolant. A slender epi- 

 pterygoid 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 pen- 

 tedactyl, with the primitive phalangeal formula, the fifth metatarsal 

 more or less hook-shaped proximally. Eight cervical vertebrae. 



Family Geckonidae. 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, compris- 

 ing 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. 



Family Euposauridae. 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. 



Family Agamidae. 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 



' [Rarely procoelous. See G. K. Noble, 1921, Amer. Mus. Novitates, No. 4. — Ed.] 

 2 [Except Liolepis. — G. K. N.] 



