GILMORE: the fossil turtles of the UINTA FORMATION 



117 



borders render it impossible to determine the character of the scallops on the 

 hinder end. The surfaces of both the carapace and plastron are roughened with 

 coarse pustular elevations, though these are more sparsely placed than in either 

 Baena sima or B inflata. With the exception of this pustular roughening the 

 surfaces are comparatively smooth, there being no longitudinal ridges or grooves, 

 such as are commonly found in many species of this genus from the Eocene. The 

 vertebral areas are a'so free from median ridges and channels. 



The nuchal scute resembles in outline that of Baena hatcheri. It has a fore- 

 and-aft diameter of about 58 mm., and a transverse diameter of 88 mm. The 



Fig. 5. Baena gigantea, carapace of C. M. No 34-11, Tyjje. About one-fifth natural size. 



unusual length of the nuchal appears to be one of the distinctive features of this 

 species. All of the sulci are distinctly impressed. At the left side of the nuchal 

 is a subrectangular first marginal, which has a length on the free border of 43 mm. 

 The total number of peripherals cannot be determined from this specimen. 



There are the usual five vertebrals and these are relatively wide, and differ 

 from those of all other Eocene Baenidae, except B. emilice, in having the fourth 

 considerably wider than long. The sides of the vertebrals posterior to the first are 



