GILMORE: the fossil turtles of the UINTA FORMATION 141 



Dimensions of Neurals. 



No. . Length. Width. 

 1 17 12 



2 13 16 



3 14.5 14 



4 13.5 14 



5 13.5 14 



6 11 14 



7 10 .....12 



8 9 10 



The peripherals of the right side above the bridge and somewhat forward of 

 the axillary notch are perfectly preserved, and, as in Echmatemys pusilla Hay, 

 have a sharp carina beginning on the third peripheral and continuing backward 

 across the bridge to the hinder peripherals. The fifth peripheral has a width of 

 19 mm.; the sixth of 18 mm.; the seventh of 20 mm.; the eighth of 18 mm. The 

 lateral peripherals from the edge of the carapace to their proximal extremities have 

 a length of 14 mm., becoming narrower toward the front of the shell. 



The sulci on most parts of the carapace are very obscure, being traceable 

 only here and there, though where they cross the neurals somewhat plainer than 

 elsewhere. The boundaries of the second vertebral can be partially determined, 

 and these indicate a very wide scute having at the center angularly pointed outer 

 borders. The second vertebral has a greatest width at the center of 58 mm.; an 

 estimated length of about 32 mm. There were four costal scutes. The costal- 

 marginal sulcus appears to have followed closely the course of the costo-peripheral 

 suture. The supracaudal scute is divided. The second suprapygal is absent in 

 this specimen. 



The impression in the matrix shows the hypoplastron to have a greatest width 

 at the midline of 41 mm. The width of the posterior lobe at the base is about 

 60 mm. Its greatest length was about 47 mm. It cannot be determined whether 

 this lobe was notched on the midline. At the center the plastron has a greatest 

 width of 84 mm. The bridge has a width of about 58 mm. The inguinal buttresses 

 rise well above the costo-peripheral sutures and articulate with both the fifth and 

 sixth costals. 



Echmatemys depressa is distinguished from all other species of the genus by 

 the greater relative widths of the vertebral scutes, the absence of a second supra- 

 pygal, and the presence of a dorsal keel. From Echmatemys megaulax (Cope), 

 which also has a dorsal keel the present species is to be distinguished by having 

 the sulci less deeply impressed and in having the costo-marginal sulcus follow the 



