184 Systematic Paleontology 



The two vertebra which are here referred to this species indicate an 

 animal of the same approximate size as the teeth and phalanges. One 

 (N'o. 2534, Gr. C), which seems to be a posterior presacral, has 

 a form quite similar to the type of Allosaurus fragilis, but relatively 

 somewhat less constricted in the middle. It agrees in having the same 

 somewhat flattened inferior surface. Anteriorly, the centrum has a 

 shallow concavity, while posteriorly it is nearly plane. The pedicels of 

 the neural arch are stout and the neural canal seems to be broader than 

 in the type of A. fragilis, possibly owing to the fact that the vertebra 

 is a more posterior one. The two agree in the depression on either side, 

 which, however, is somewhat less marked in the present species. 



DIMENSIONS 



Length 90.0 mm. 



Least diameter of centrum 68.5 mm. 



Diameter of anterior face as preserved 105.0 mm. 



Diameter of posterior face as preserved 95.5 mm. 



HeigM of centrum 85.0 mm. 



The anterior caudal vertebra (No. 2614 a, G-. C.) is that of 

 a young individual, as the neural arch had not coossified with the 

 centrum. Internally it seems to have been composed of rather coarse, 

 cancellous tissue with no trace of an internal cavity, as in the type of 

 Antrodemus, as figured by Leidy.^ 



The anterior face is slightly concave, the posterior one nearly plane; 

 and while the centrum is constricted decidedly in the middle there is 

 no trace of the lateral depressions seen in the presacrals. 



DIMENSIONS 



Length 107 mm. 



Least diameter 59 mm. 



Diameter anterior face 101 mm. 



Diameter posterior face 93 mm. 



Height of centrum 92 mm. 



The first phalanx of the second digit is represented by the proximal 

 half (No. 2536, G. C), and is peculiar for its height as compared 

 with its width and the two very prominent ridges on the inferior face. 



1 Leidy, Rept. of U. S. Geol. Surv. of Terr., vol. i, 1873, pi. xv, fig. 18. 



