3*4 



SAMUEL W. WILLISTON 



median line and the right half has been preserved in articulation 

 with the vertebrae lying upon its side. In this specimen, the slight 

 distortion is in the other direction; its height posteriorly is a little 

 too great. From a study of all these specimens, however, one can 

 determine almost exactly the elevation of the posterior part of the 

 skull, about as I have figured it in the restoration. Whence it 

 follows that in all the figures hitherto given, including my own, the 

 skull is shown too much flattened posteriorly, and the orbits too 



Fig. 4. — Labidosaurus. Anterior dorsal vertebrae. 

 in front; C, from below; D, from above. Natural size. 



A, from the side; B, from 



ovate in form when seen from the side. In reality the orbits 

 seen from the side are almost circular in outline. 



Vertebrae. — The peculiar structure of the vertebrae, which 

 Labidosaurus shares for the most part with Captorhinus, has been 

 described sufficiently well by Case, and will be seen from the 

 accompanying figure (Fig. 4). Vertebrae of this type are known 

 exclusively from the Texas deposits, with one exception, a specimen 

 of a large form found by Professor Case in the El Cobre Canon. 

 I believe that when the skull of this genus is discovered it will prove 

 to be of the Labidosaurus type. I may add that the horizon of 

 this specimen is rather high up in the Cobre deposits. 



