45 8 



FOSSIL TURTLES OP' NORTH AMKRICA. 



T. pertemas Cope, of the Blanco beds of Texas (op. cit. p. 47, figs. 1, 2), is a large species 

 with the bones of the carapace and plastron not exceeding about 6 mm. in thickness, except 

 at the borders. The bones are also devoid of sculpture. The depth of the posterior notch at 

 the plastron is very nearly half the width of the plastron at the bottom of the notch. In T. 

 campester the depth of the notch is not one-third of the width of the plastron at the point 

 indicated. The vertebral scutes of T. pertenuis were much wider than in T. campester. Those 

 of our specimen of the latter would be about 250 mm. wide if their ratio to the length of the 

 animal were the same as in T. pertenuis. 



T. turgida (Proc. Amer. Philos. Soc, x.x.x, 1892, p. 127) has not been figured. It also is 

 from the Blanco beds of Texas. So far as known it is a small species. The anterior lip is 

 described as resembling two "flattened cones apprest together, whose vertical diameter exceeds 

 the transverse and whose subconic apices are separated by a deep notch. " Relatively to the 

 size of the animal the hinder plastral notch was much wider than it was in T . campester. Other 

 important differences appear on comparison of the descriptions. 



Testudo obtusa (Leidy). 

 Figs. 614, M 5. 



Eupachemys obtusus, Leidy, Jour. Acad. Nat. Sci. (2), vni, 1877, p. 232, plate xxxiv, figs. 4, 5. Hay, 



Bibliog. and Cat. Koss. Vert. N. A., 1902, p. 448. 

 Eupachemys rugosus, Leidy, Trans. Wagner Free Instit., 11, 1889, p. 29 (errore). 



Dr. Leidy's Eupachemys obtusus was based on a single peripheral bone which was sent 

 to him by Prof. F. S. Holmes, this bone having been found in the phosphate beds of Ashley- 

 River, South Carolina. The exact age of the fossil is impossible of determination; but its time 

 of existence was undoubtedly somewhere between the end of the Eocene and the beginning of 

 the Pleistocene. Dr. Leidy founded for this turtle the new genus Eupachemys, but he did not 

 attempt to define it. This name and the fact that he compared the bone with a peripheral of 



Emys seem to indicate that he believed 

 the relationships of the animal to be 

 with the aquatic emyds. The bone 

 was evidently derived from a turtle 

 about a meter in length. None of the 

 Emydidae attains such great size, and 

 without other evidence the probability 

 would be that the animal was a species 

 of Testudo. To this genus it is here 

 referred. There are some reasons for 

 suspecting that it is the same turtle 

 that was later described by Leidy 

 under the name Testudo crassiscutata. 

 However, until more is known about 

 the two forms it seems best to retain 

 them distinct. 



Dr. Leidy regarded the bone de- 

 scribed by himself as probably the 



614. 



Figs. 614 and 615. Testudo obtusa. 

 of type peripheral. 



6.5. 

 Outline and section 



xj. 



614. Outline of upper surface. 615. Section at posterior end. 



eighth of the left side. If this were true the anterior end might be expected to be thicker 

 than the posterior; but of this we have no evidence. The fore-and-aft extent of the bone 

 (fig. 614) is 120 mm. The height at the posterior end is 136 mm.; the greatest thickness, 

 72 mm. At the costal border the bone is thinned down to 15 mm. The lower, or tree, border 

 (fig. 615) is obtuse, a rare condition in turtles. What Leidy regarded as the upper surface, and 

 probably correctly, rises in a prominent fore-and-aft ridge just below the middle of the height. 

 From this ridge to the costal border the surface is concave; from the ridge to the tree border, 

 it is plane. The lower, or inner, surface is strongly convex from the costal to the tree borders. 

 The upper surface of the bone is rough and eroded. It exhibits no sulci separating the 

 marginal scutes. The inner surface is smooth and presents a longitudinal sulcus running 

 along near the costal border and more feeble indications of another that ran between the two 



