292 FOSSIL TURTLES OF NORTH AMERICA. 



Plate 45, fig. 2, represents the inguinal region of the hypoplastron and the adjacent part of 

 the xiphiplastron, seen from above. The free border is acute. The beveled, horn-covered 

 surface, on the upper side, is 18 mm. wide and attains a thickness of 9 mm. At its inner border 

 the thickness falls off suddenly to 6 mm. The lines of growth of the femoral scutes are dis- 

 played on this surface. Evidently there have been no strongly developt inguinal buttresses 

 extending inward on the plastron such as we find in Echmatemys. 



Fig. 3 of plate 45 presents a view of the upper side of the left xiphiplastron. 



Fig. 360 shows the same bones viewed from below. Near the anterior border of the 

 fragment of the hypoplastron is seen the abdomino-femoral sulcus. The femoro-anal sulcus 

 crost the free border at the hinder end of the fragment. 



No. 6024 furnishes the front of the nuchal as far backward as the bone was thickened, 

 and the hinder portion of the left xiphiplastron. On the lower surface of the nuchal, at the 

 midline, the thickened portion extends backward only about 12 mm.; but toward each side 

 this increases to 19 mm. The lines of growth of the first marginal scutes are very conspicuous 

 on this surface. On the upper side of the bone the nuchal scute is observed to be 9 mm. long, 

 3 mm. wide in front, 10 mm. wide behind, and to be more deeply notcht posteriorly than in 

 the type. The piece of xiphiplastron is very flat on the under side and has the free border 

 acute. The beveled surface on the upper side is 1 1 mm. wide and ornamented with the growth 

 lines of the femoral scute. There was a notch in the hinder end of the lobe. 



No. 6019 is the epiplastron of a considerably smaller individual than the type. It differs 

 especially in having the upper surface of the lip less swollen, the greatest thickness being only 

 about 6 mm. This surface shows the lines of growth of the gulars. 



No. 6020 furnishes a portion of the epiplastral lip and a fragment of the hyoplastron. 

 The individual seems to have been slightly larger than the type. The upper surface of the lip 

 is strongly folded. The fragment of hyoplastron belongs behind the entoplastron and is rep- 

 resented in fig. 360. Its thickness is only about 4 mm. The pectoro-abdominal sulcus crost 

 it about 8 mm. in front of the hyohypoplastral suture. 



C. morrisite resembles in some respects Echmatemys pusilla, especially in the epiplastral 

 lip. For differences see the last-named species. 



This species is named in honor of Mrs. Lindsey Morris Sterling, in recognition of the 

 skill, accuracy, and artistic taste shown by her in the preparation of the great majority of line 

 drawings in this work. 



Clemmys hesperia Hay. 

 Plate 45, figs. 4-7; teit-figs. 361-365. 

 Clemmys hesperia, HAY, Bull. Geol. Dept. Univ. Calif., Ill, 1903, p. 238, figs. 1-5. 



As the type of this species, is taken the bone bearing number 2219 of the Paleontological 

 Department of the University of California. This is the left hyoplastron, having the outer pos- 

 terior portion, which enters into the bridge, missing. Plate 45, fig. 4, and text-fig. 361, represent 

 it of the natural size and viewed from below. The sutural edges are present which met the 

 hyoplastron of the opposite side, the postero-lateral border of the entoplastron, the hinder 

 extremity of the epiplastron, and the front of the hypoplastron. As will be observed, the 

 humero-pectoral sulcus, represented by a dotted band, crosses the entoplastron, while the 

 pectoro-abdominal sulcus is well back on the hyoplastron. The structure of these parts is 

 identical with that of the genus Clemmys, represented to-day on the Pacific Coast by Clemmys 

 marmorata. The free border of the bone between the humeral buttress and the epihyoplastral 

 suture is acute. The bone thickens until it reaches a thickness of 7 mm. where the suture just 

 named meets the entoplastron. At the inner posterior angle the bone is only 3 mm. thick. 



In lot No. 2179, believed to be from the Rattlesnake beds of the Pliocene but possibly 

 from the Mascall beds of the upper Miocene, there is a portion of a left hyoplastron which 

 lacks the free border, but which as far as it is represented is identical with the specimen 

 above described. The writer regards it, therefore, as belonging to the same species and to the 

 same formation. In this lot are included also a portion of the right epiplastron (plate 45, fig. 

 5; text-fig. 362), the first right peripheral bone (plate 45, fig. 6; text-fig. 363), a right periph- 

 eral, apparently the eighth or ninth, and some other fragments. The epiplastron has the 



