GILMORE: the fossil turtles of the UINTA FORMATION 



131 



The peripherals are high. On the right side immediately posterior to the in- 

 guinal notch they extend upward 74 mm. above the margin of the shell; the most 

 posterior one 45 mm.; the most anterior one 56 mm. above the margin. 



The suprapygal is 41 mm. long. The second suprapygal is 52 mm. long, and 

 93 mm. across the middle, and 42 mm. where it joins the pygal. The pygal has a 

 length of 32 mm., a width of 55 mm. The posterior boundary of the fifth vertebral 

 crosses the second suprapygal 20 mm. anterior to its posterior margin. Both the 

 pygal and second suprapygal are strongly arched above the tail. 



The vertebral scutes are long. The sides of the median three are slightly 

 bracket-shaped, the fourth, as in Echmatemys uintensis Hay, is strongly urn-shaped. 

 The dimensions of the vertebrals are given in the accompanying table. 



Dimensions of Vertebrals. 



e, estimated. 



There appear to be twelve marginals in the complete series of one side, and 

 some rise to the proximal ends of the peripherals. On the right side the eighth 

 peripheral is crossed by the marginal sulcus 21 mm. below the costo-peripheral 

 suture. The most posterior marginal scute is 53 mm. high from the margin of the 

 shell. 



The plastron is perfectly preserved and characters observed in the plastron 

 show the distinctness of Echmatemys douglassi from all other described forms. The 

 plastron has a maximum length of 407 mm. At the center it measures 374 mm. in 

 length. The front of the anterior lobe is broadly and deeply emarginated, the 

 emargination lying between two toothed projections which extend forward at either 

 side, as is well shown in Fig. 12. On account of this emargination there is no well- 

 defined lip. The anterior lobe is broad and at its base measures 190 mm. with a 

 length at the center of 95 mm. The length therefore is exactly 50 per cent, of the 

 width. The lateral borders of the lobe in front of the axillary notches are slightly 

 concave, then expanding a little to the posterior ends of the epiplastra, then turning 

 inward to the toothed projections at either side of the lip. The latter is wide, 

 measuring 94 mm., which is nearly one-half of the total width of the lobe. 



The posterior lobe has a greatest length at the center of 130 mm. ; a width at 

 the base of about 199 mm. The hinder lobe is considerably constricted at the anal- 



