10 



Annals of the Carnegie Museum. 



The pygal measures 40 mm. transversely and 16 mm. antero- 

 posteriorly; at the median notch it is only 10 mm. fore-and-aft. As 

 in G. plicatulus there are two suprapygals.^ The form of these bones 

 is well shown in Fig. i. The greatest width of each is 53 mm.; the 

 antero-posterior diameter of the posterior element at the midline is 

 18 mm.; the same measurement of the anterior element is 14 mm. 



The costal plates narrow in succession from before backward, the 

 eighth being relatively wider than in G. plicatulus. 



The plastron is comparatively narrow. It is thin and fiat, except 

 on the hinder two-thirds of the posterior lobe, which is shallowly 

 concave transversely. It has a length of 224 mm., and extends 

 slightly in advance of the border of the carapace. The anterior lobe 

 is 68 mm. long, its width at the base being 87 mm. The borders are 

 relatively thin and rounded. 



The entoplastron measures 55 mm. in length, and 55 mm. in width. 

 It is more pointed behind than in G. plicatulus, resembling in this 

 respect the entoplastron of G. depressiis Hay. 



Fig. 2. Glyplops utahensis. Plastron of type, No. 3412. One-third natural size. 



The mesoplastra dift"er in width at the midline, the right being 2a 

 mm.; the left 23 mm. The hypoplastrals meet on the midline for 

 about 46 mm. The xiphiplastral bones have their greatest length, 

 45 mm., at their median junction. 



1 Hay, O. P., Proc. U. S. Nat. Museum, Vol. 35, 1908, p. 162, Fig. i. . 



