338 



FOSSIL TURTLES OK NORTH AMERICA. 



thickened junction of the fifth and sixth costals is an excavation for the inguinal buttress. 

 This ascended about one-third the distance from the lower border of the costal to the neural 

 border. 



The first, second, and third peripherals have acute free borders and remains of the bridge 

 peripherals show that a sharp carina from the third peripheral continued backward to the 

 hinder peripherals. The costo-marginal sulci run just below the costo-peripheral sutures. 

 The second peripheral has a height of 15 mm.; the third, of 12 mm.; the eighth and ninth, of 

 15 mm. The eighth, ninth, and tenth are only slightly concave above. In fig. 446 the last- 

 mentioned peripherals are placed too near the midline. Most of the vertebral scutes are 

 broader than long. 



The plastron (fig. 446) lacks the hinder extremity. Its total length was not far from no 

 mm. The anterior lobe is 38 mm. long, 58 mm. wide. The epiplastral lip is truncated, 25 mm. 

 wide, and furmsht with a blunt tooth on each side. On the upper side the lip is thickened 

 backward for a distance of 16 mm., where there is a sudden offset. The thickness of the lip 



445- 



FlGS. 445 AND 446. Echmatemys pusilla. Plastron and carapace of type. X 



441;. Plastron. 



446. Carapace. 



is about 9 mm. from one side to the other. The entoplastron is elongated and pointed in front. 

 Its length is 26 mm., its width 8 mm. The hinder lobe of the plastron has a width of 61 mm. 

 at the base. Its free borders are acute. The horn-covered surface on the upper side is 1 1 mm. 

 wide and shows distinct impressions of the growth of the scutes. The thickness at the hypo- 

 xiphiplastral suture is 6 mm. The inguinal buttress extends inward from the free border of 

 the lobe little more than one-third the distance to the midline. 



The gular scutes overlap somewhat the entoplastron, as do likewise the pectorals. The 

 latter scutes reach backward to the hyohypoplastral suture, a condition not known in other 

 species of the genus. 



In his monograph of 1873, as cited at the head of this article. Dr. Leidy described, 

 as the young of his Emys wyomingensis, a small turtle which had been sent to him from 

 Fort Bridger, Wyoming, by Dr. Carter. This specimen is now in the collection of the Phil- 

 adelphia Academy. 



The specimen agrees in all essential respects with the type of E. pusilla. It furnishes a 

 large part of both carapace and plastron. The nuchal bone and all the neurals are present, 

 except the fifth. There are 2 suprapygals. Both first costals are preserved and wholes or 

 parts of all those of the left side. The first right peripheral is in its place. All the peripherals 

 of the left side are present, except the fourth and sixth. The pygal is missing. Of the plastron 



