305 



The posterior border of the bone is 5 mm. thick, while the anterior sutural border is 8 mm. 

 thick. This is due evidently to the formation of a ridge on the fifth and sixth costals for the 

 reception of the inguinal buttress. 



No. 1173 f tne American Museum forms Cope's third specimen. There is present a 

 portion of the first costal with the articular surface for the axillary buttress. There is a rough 

 drawing by Cope on which this bone is traced as belonging to the xiphiplastrals. This bone 

 belonged to a much larger individual than that represented by No. 1181, but the scar for the 

 buttress is no longer. This costal was at least 35 mm. wide and is 7 mm. thick where it joined 

 the first and second peripherals. The outer surface is smooth. With this lot is a portion of the 

 third right peripheral, excavated at the hinder end to form a part of the sternal chamber. Fig. 

 387 represents the sutural surface which articulated with the second peripheral. It will be 

 seen that the free border is broadly rounded. Fig. 388 presents the outlines and a view of 

 the anterior articular surface of a hinder free peripheral. This is recurved and has an acute 

 edge. The surface is uneven; and the sulci are narrow but sharply imprest. 



No. 1258 appears to represent another portion of Cope's principal specimen. Among the 

 bones is an entoplastron, but not the one described by Cope. The one which furnisht Professor 

 Cope's figure 12 is not one-half the size of nature, as stated, but four-sevenths. The breadth of 

 the entoplastron of No. 1258 is 37 mm., its antero-posterior extent 24 mm., 2 mm. less than 

 that given by Cope. The longitudinal sulcus is very obscure, while the humero-pectoral 

 plainly crosses the bone about the middle of the length. The internal face of the bone is badly 

 weathered, so that little regarding the position of the bone can be determined therefrom. 

 The anterior border is damaged for most of its extent. There is a piece of the left hyoplastron 

 present, but it is impossible to say whether the two bones belong together. What appears to be 

 the free border of the right hyoplastron is present. The edges are acute. The beveled surface 



on the upper side attains a width of 15 mm. and a 

 thickness of 9 mm. Two portions of the epiplastra 

 are present, but their proper positions are difficult to 

 determine. They are acute-edged and they thicken 

 rapidly, the beveled surface attaining a thickness of 

 II mm. and a width of 14 mm. At the inner border 

 the thickness is diminisht suddenly. 



The fragment of the hinder lobe figured by Cope 

 (his fig. 13) appears to indicate the presence of a 

 FIGS. 387 AND $S.-Echmatemys testu- we ll-develo P t inguinal buttress, whose base extended 



A"MN H XI ' " 73 inward about 20 mm - from the free borden At the 



suture between hypoplastron and xiphiplastron the 

 387. Section at anterior end of third right peripheral, beveled upper border has a width of 15 mm. and here 



388 ' "^Tr^re! 1 ' 5 the bone is 8 '5 mm ' thick ' The inner border f the 



beveled surface is bounded by a considerable groove. 



The free border is acute. The lower surface of this hinder lobe was flat transversely and 

 turned up posteriorly. The abdomino-femoral sulcus crost the plastron somewhat in front of 

 the inguinal notch. 



Cope believed there was an undivided intergular, but the writer finds nothing to sustain 

 this opinion, and it is improbable. Undoubtedly the species is an emyd, and the presence of 

 an intergular, single or divided, would probably be unique. The proximal end of a costal, the 

 second or the fourth of the left side, has a width of 20 mm. and a thickness of 8.5 mm. The 

 longitudinal sulcus traverst the bone at a distance of 7 mm. from the neural border, showing 

 again that the vertebral scutes were very narrow. While the surface is uneven, there is no 

 swelling outside of the sulcus, differing thus from the others described. 



Echmatemys euthneta (Cope). 

 Plate 46, fig. i; text-figs. 389-391. 



Emys euthnetus, COPE, Sixth Ann. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 628. 

 Emys euthneta, COPE, Vert. Tert. Form. West, 1884, pp. 129, 133, plate xviii, figs. 34-42. HAY, 

 Bibliog. and Cat. Foss. Vert., 1902, p. 447. 

 20 



