GILMORE: the fossil turtles of the UINTA FORMATION 



125 



plastron, a portion of the central part of the carapace, including the third, fourth, 

 and fifth neurals with portions of the second, third, and fourth costals: and a small 

 piece of the fifth, sixth, and seventh costals with abutting peripherals. It was 

 collected in the badlands of South Bitter Creek, Wyoming, from the beds of the 

 Washakie Basin. 



I have carefully compared the specimens before me with the above mentioned 

 type and except for differences in size, find them, so far as they can be contrasted, 

 remarkably similar. The broad, hatchet-shaped anterior lobe so characteristic of 

 Echmatemys septaria is duplicated in these specimens. 



In the type of Echmatemys callopyge the front two-thirds of the first vertebral 

 lies wholly within the lateral borders of the nuchal plate, and, although relatively 

 wider, this is also true of specimen C. M. No. 2157, but specimen C. M. No. 2371 

 has the antero-lateral angles of the first vertebral extending across the lateral 

 sutures of the nuchal. In a specimen identified by Hay as pertaining to Ech- 

 matemys septaria (See Fossil Turtles of North America, Fig. 415, p. 320) the first 

 vertebral extends entirely over the lateral boundaries of this plate. From the 

 intermediate condition observed in the present specimens, the first vertebral 

 would appear to be subject to considerable variation and therefore its narrowness 

 cannot be rehed upon as a constant specific difference. Specimen C. M. No. 2371 



Fig. 10. Echynatemys callopyge Hay. Plastron of C. M. No. 2371. One-fourth natural size. 



