ART. 16 



FOSSIL REPTILES FROM MONTANA GILMORE 



Measurements 



15 





Cervicals 





Third 



Fifth 



Seventh 



Greatest length of centrum.- __ . _ _ __ 



Mm. 



82. 5 



107 



1 150 



39 



Mm. 



55 

 120 

 172 



53 



Mm. 

 66 



Greatest width of centrum 



123 



Greatest height over all 



Width of neural canal 



187 

 48 







> Estimated. '^ 



Dorsal vertebrae. — There are 10 vertebrae of the dorsal region rep- 

 resenting all parts of the column. About half of these are per- 

 fectly preserved, while the other half are either much distorted by 

 crushing or important parts are missing. 



The centra are relatively short and amphicoelous throughout the 

 series; articular faces expanded and sides deeply excavated (fig. 

 lOA). In the dorsals the transverse diameter of the centra always 



Figure 10. — Anterior dorsal vertebra of Palaeoscincds rdgosi- 

 DENS. Type. No. 11868, U.S.N.M. A, lateral view ; B, Anterior 

 VIEW. Both figures one-third natural size 



exceeds the vertical. The centra of greatest length are near the 

 middle of the thoracic region. In the anterior half of the column 

 the centra have a well developed median keel bordered on either side 

 by shallow depressions. Posteriorly, however, the distinct keel 

 disappears and the bottom of the centra is obtusely rounded. The 

 neural arch is low and massive throughout (fig. lOB). The trans- 

 verse processes are massive, of moderate length, and project obliquely 

 upward but not so sharply as in Stegosaurus. They are deeply 



