292 



THE OSTEOLOGY OF THE REPTILES 



Family Anchisauridae. Smaller and more slender theropods. 

 Vertebrae amphicoelous. Teeth compressed, more or less recurved. 

 Astragalus without ascending process. 



Upper Triassic. Anchisaurus Marsh, Megadactylus Hitchcock, 

 Ammosaurus Marsh, Connecticut Valley. Thecodontosaurus Riley 

 and Stutchbury, England, Africa, AustraUa. Massospondylus Owen, 

 South Africa. Zanclodon Plieninger, Sellosaurus Huene, Europe. 



[No MS. was found for (i) the Coelurosauria, containing several 

 families and numerous genera of light-limbed saurischian dinosaurs, 

 including the Ornithomimidae, (2) the Megalosauria group of the 



Fig. 187. Skeleton oi Gorgosaurus (Saurischia). After Lambe. One thirty-sixth natural size. 



Jurassic, and (3) the Deinodont group of the Cretaceous. For group 

 I see papers by Osborn 191 7 {Bulletin, Amer. Mus. Nat. Hist., vol. 

 XLiii), von Huene 192 1 {Acta Zoblogica, Bd. II) ; for groups 2 and 3 

 see Matthew and Brown, 1922 {Bulletin, Amer. Mus. Nat. Hist., 

 vol. XLVi). — Ed.] 



B. SUBORDER SAUROPODA (OPISTHOCOELIA, CETIOSAURIA) 



Quadrupedal, semiplantigrade, herbivorous dinosaurs, with long 

 neck and tail and small skull. Postfrontal sometimes present. Teeth 

 subcylindrical, with a thickened, spoon-shaped crown, in a single row, 

 and more or less restricted to anterior part of jaws, the premaxillae 

 with teeth; no predentary. No coronoid process to mandible. The 

 anterior, sometimes all, presacral vertebrae opisthocoelous, with a 

 more or less developed hyposphene-hypantrum articulation, and with 

 hollow, lateral cavities in centra. Four or hve sacrals, twenty-six or 



