3 i6 



FOSSIL TURTLES OF NORTH AMERICA. 



The hinder lobe is 1 1 mm. long and 160 mm. wide, the length being thus 70 per cent, of 

 the width. There is a posterior notch of considerable size. The beveled surface on the upper 

 side of the lobe, at the hypoxiphiplastral suture, is 29 mm. wide. 



The gular scutes differ in size. That on the left is 48 mm. long. The humerals are 42 mm. 

 long; the pectorals, 72 mm.; the abdominals, 84 mm.; the femorals, 69 mm.; the anals, 55 

 mm., measured to the end of the plastron. The axillary scutes are large, but they do not 

 reach backward to the fifth marginals. The inguinals are large and extend forward so as 

 just to touch the sixth marginals. 



The inguinal buttresses extend far inward reaching at least half-way from the free border 

 of the base of the hinder lobe to the midline. 



No. 6088 of the American Museum is referred to E. haydeni. It was found at Henry Fork 

 Hill, 100 feet below the white stratum, in horizon C. The carapace had a length of about 400 

 mm. For a view of the upper side of the border of the hinder lobe see fig. 410. 



E. haydeni is to be distinguisht from E. wyomingensis by the axillary and inguinal but- 

 tresses. In the latter species the inguinal buttresses extend inward not more than one-third the 

 distance from the free border of the hinder lobe to the midline; while in E. haydeni they extend 



410. 



FlGS. 409 and 410. Echmatemys haydeni. Portions of lobes of plastron. Xi- 



409. Upper surface of anterior lobe. No. 3943 A.M.N. H. 



410. Upper surface of free border of hinder lobe of plastron. No. 6088 A.M.N.H. 



inward at least half-way to the midline. Usually, if not always, the fourth neural of E. haydeni 

 is octagonal, but occasionally this is true of the same neural of E. ivyomingensis. Usually the 

 upper side of the epiplastral lip of E. wyomingensis is short, the thickening not extending back- 

 ward so far as in E. haydeni. 



E. shaughnessiana is to be distinguisht by the relatively wider vertebral scutes and the 

 thickened and obtuse free borders of the front of the carapace. 



Echmatemys stevensoniana (Leidy). 

 Plate 48, figs. 1, 1; text-figs. 411-413. 



Emys stevensonianus, Leidy, Proc. Acad. Nat. Sci. Phila. 1870, p. 5. 



Emys stevensoni, Leidy, Ann. Report U. S. Geol. Surv. Wyoming, etc., 1870 (1871), p. 366. 



Emys wyomingensis, Leidy, Ann. Report U. S. Geol. Surv. Montana, etc., 1871 (1872)^.367 (in part); 



Contrib. Ext. Fauna West. Terrs., 1873, p. 141, plate ix figs. 2-4. Hay, Bibliog. and Cat. 



Foss. Vert. N. A., 1902, p. 448 (in part). 



Dr. Leidy's type ot the present species was collected somewhere in the vicinity of Fort 

 Bridger, Wyoming, and therefore probably in the lower portion of the Bridger Eocene. His 

 specimen consisted of a portion of a carapace showing the whole series of neurals and the 



