460 Bulletin American Museum of Natural History. [Vol. XIX, 



A possible objection to this hypothesis is that the teeth, 

 while distinctively prehensile, are not so serrate or trenchant 

 as in Cceliinis. They are, however, quite as sharp as in the 

 varanoid and other lizards which are known to capture and 

 feed upon small birds. 



The preniaxillary contains 4 teeth, the most anterior of 

 which is the largest tooth in the upper jaw. The maxillary 

 retains 10 teeth, of which the fifth is the largest. In the 

 dentary are 12 teeth. In both jaws the teeth occupy a 

 rather short space, a little more than one third the entire 

 length of the skull, and gradually decrease in size posteriorly. 

 The premaxillary teeth are slightly worn on the posterior 

 surface. There are two antorbital openings, a smaller within 

 the maxillary, and a larger bounded posteriorly by the co- 

 alesced lachrymal and jugal. The orbits are very large, 

 bounded posteriorly by the united postorbito- frontal, which 

 connects by a slender bar with the squamosal. The depres- 

 sion of the quadrate extends the latero-temporal fenestra 

 vertically. The jaw is relatively long and slender, with ses- 

 sile coronoid process; the sutures have not been determined. 

 The cervicals are gently opisthocoelous, the dorsals are amphi- 

 coelous, the posterior face being slightly more concave than 

 the anterior; the caudals are gently amphicoelous. The 

 neural arch only of the supposed fifth cervical is preserved. 

 The supposed tenth and eleventh cervicals are moderately 

 elongate, slightly opisthocoelous, with separate attachments 

 for the capitulum on the anterior portion of the centrum, and 

 for the tuberculum on the broad diapophysial expansion of 

 the neural arch; the zygapophyses are large and the neuro- 

 central suture is faintly indicated. In the supposed second 

 dorsal or thirteenth presacral the capitulum is still borne on 

 the centrum; behind the capitulum is a pit (paracoele), a feature 

 also observed in the supposed fifth dorsal ; the diapophysis is 

 narrow; the head of the rib gradually rises to the junction 

 between the centrum and neural arch, as in other dinosaurs. 

 The four sacrals are firmly coalesced. The sacral ribs are 

 still suturally distinct and attached chiefly at the sides of the 

 centra, although the third sacral rib partially overlaps the 



