GILMORE: the fossil turtles of the UINTA FORMATION 



149 



the lip is 22 mm. thick, but posteriorly it increases to 27 mm., behind which the 

 plastron is deeply excavated. On the upper surface of the lip there is a slight 

 median elevation. Transversely the whole lip is broadly convex rounding down 

 at the sides to a subacute edge. 



Fig. 20. Plastron of Hadrianm utahensis. Type. C. M. No. 2343. One-fourth natural size. 



The entoplastron is rhombic in form, being 97 mm. long and 95 mm. wide. 

 The gular scutes reach, but do not overlap, this bone. In this respect this specimen' 

 differs from all of the described species of the genus. The bridge has a greatest 

 width of 210 ram. 



The posterior lobe has a greatest length of about 140 mm.; a greatest width 

 of 230 mm. at the inguinal notches. The posterior lobe is shallowly notched on 

 the midline. This notch has a greatest depth of 10 mm. Immediately behind the 

 inguinal notches the borders of the lobe have a thickness of 27 mm. and are rounded 

 dorso-ventrally. The border at the anal sulcus is 18 mm. thick. The free border 

 of the entire lobe a short distance posterior to the inguinal notches is bevelled off 



