EMYDID^E. 3OI 



The type specimen was obtained from the Wasatch beds of New Mexico. The more exact 

 locality is given as the Gallmas River. 



In his great work on the Vertebrata of the Tertiary Formations of the West, publisht in 

 1884, Cope exprest the opinion that his Emys cibollensts may have been founded on a larger 

 individual of his Emys euthneta of the "red beds" at Black Buttes, Wyoming. To the present 

 writer, after comparing Cope's descriptions and figures and the types of the two forms and after 

 study of such materials of E. euthneta as are accessible, Cope's opinion of 1884 seems erro- 

 neous, for reasons to be mentioned below. 



The individual forming Cope's type was somewhat smaller than the one which formed the 

 type of his E. lativertebralis. Its plastron was about 250 mm. long, carapace about 310 mm. 

 When Cope described this species he regarded its relationships as being with his Emys lati- 

 vertebralis, but he found the peripheral bones of the latter larger and thinner, and both the 

 anterior lobe of the plastron and the entoplastron relatively longer. 



Cope figures no costal bones, but he gives the width of one as 22 mm., the thickness as 

 6 mm. A costal of E. lativertebralis had a width of 24 mm. and a thickness of 5 mm. 



Of the peripheral bones Cope says that they are not, or but little, recurved. He figures 

 two of these, but he does not state whether they are anterior or posterior peripherals. Evidently 

 both were imperfect. They probably belonged behind, and included the portion between the 

 free border and the costo-marginal suture. Cope gives the length of one peripheral as being 

 30 mm. and its thickness as 9 mm.; but the thickness of those figured must have been about 

 12 mm. The peripherals of E. lativertebralis differ in being higher and thinner. On the other 

 hand, the posterior peripherals of E. euthneta were more recurved. 



The anterior lobe of the plastron to the hinder border of the entoplastron is 65 mm. long. 

 The anterior lip (fig. 379) projected somewhat and is slightly concave in outline. At each side 



is a rather prominent tooth, but there is no cleft separating it 

 from the remainder of the lip as there is in E. lativertebralis. 

 The width of the lip, measured to the gulo-humeral sulci, is 

 54 mm. The thickening on the upper surface of the lip extended 

 backward 23 mm. From each lateral tooth there extends back- 

 ward a broad ridge. At the hyoepiplastral suture the beveled 

 surface is 23 mm. wide. The entoplastron has a length of 36 

 FIG. tf<). Echmatemys cibol- mm -> a width of 55 mm -> and a thickness of 7 mm. As stated 

 lensis. Epiplastral lip of type, by Cope, the bone was transversely diamond-shaped. To the 

 Xj. No. 2576 U. S. N. M. present writer, the epiplastral lip appears to be quite different 



from that of Emys euthneta. 



The hinder lobe had a total length of 95 mm. and at the rear was a deep notch. There was 

 a broad beveled area at the border of the upper surface, and at the hypoxiphiplastral suture 

 this was 22 mm. wide. This surface appears to have been strongly imprest by the lines of 

 growth of the horny scutes. In Cope's Emys euthneta this surface was relatively narrow (Vert. 

 Tert. Form. West, plate xviii, fig. 42). 



The estimate of the present writer is that the length of the anterior lobe of E. lativertebralis 

 equaled 0.75 of the length of the hinder lobe; in E. cibollensis about 0.68. 



The arrangement of the scutes of the anterior lobe of E. cibollensis is quite different from 

 that of E. lativertebralis, since the gulars of the former do not reach backward to the ento- 

 plastron and the humerals overlap extensively this bone. The gulars of the present species had 

 a length of 25 mm. and, taken together, a width of 54 mm. In E. euthneta the gulars had 

 evidently a length fully equal to their combined widths. 



There appears to be no good reason why this species should not be referred to Echmatemys. 



Echmatemys ? megaulax (Cope). 

 Plate 45, figs. 14, 15; teit-figs. 380-383. 



Emys megaulax, COPE, Sixth Ann. Report U. S. Geol. Surv.Terrs., 1872 (1873), p. 628; Vert. Tert. Form. 



West, 1884, pp. 129, 132, plate xviii, figs. 26-33. HAY, Bibliog. and Cat. Foss. Vert. N. A., 1902, 



p. 448. 

 Emys pachylomus, COPE, Sixth Ann. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 629. 



