402 



FOSSIL TURTLES OF NORTH AMERICA. 



Figs. 506-508. Testudc exornata 

 of type. X 1. 



t;o6. Fragment of first costal. 



507. Proximal end of sixth costal. 



508. Proximal half of third or fifth costal 



Costals 



the Cypress Hills, Assiniboia. These costals are remarkable for their thickness, the deeply 

 imprest sulci, and the strongly markt lines of growth of the horny scutes. 



Figs. 6 and 7 of plate 66 represent the distal half of the left fifth costal, which is taken by 

 Mr. Lambe as the type of the species. Fig. 6 shows the outer surface. This is 12 mm. wide at 

 the upper end, 10 mm. at the lower. It might be taken for the bone of a young animal were 

 it not for the great thickness. The anterior sutural border has a thickness of a little more than 

 4 mm. From this border the bone thickens rapidly, so that the posterior border, at the lower 

 end of the hone, is 8 mm. thick. Seen from the inner surface (fig. 7) the bone presents, on the 

 hinder half of its width, a prominent half-ridge, which was evidently completed on the succeed- 

 ing costal. The larger portion of the ridge has been on the sixth costal, and has been developt 

 to receive the inguinal buttress of the plastron. It looks indeed as if this buttress had ascended 

 about 1 5 mm. above the border of the costals and had been articulated with both the fifth and 

 the sixth, but principally with the latter. So far as the writer is aware, in other species ot Testudo 



the buttress articulates only with the sixth 

 costal. At the lower end of the fifth costal is 

 a pit for a process of the seventh peripheral. 

 It is evident that this costal was much broader 

 at the proximal end than at the distal. 



There is present a portion ot the left first 

 costal plate (fig. 506). In this figure the 

 upper border was directed toward the head, 

 the rioht hand border toward the first neural. 

 At the upper end the fore-and-aft width of 

 the bone was about 30 mm. From this it is 

 estimated that the length of the carapace was 

 about 200 mm. At its posterior border the 

 bone is 4.5 mm. thick. On the inner sur- 

 face is a ridge which past upward into the 

 head of the rib. The outer surface of the bone is markt by the lines ot growth of the 

 first costal scute. Fig. 507 represents the outer surface of the proximal end ot another costal, 

 probably the sixth costal of the left side. Where the bone joined the sixth neural it is 8 mm. 

 thick. The sulci are narrow, but deeply imprest. The outer surface shows the lines ot 

 growth of the scutes. At its upper end the bone is 15 mm. wide and appears to have expanded 

 toward the distal end. 



Fig. 508 represents a costal of a young individual, evidently the third or the fifth, probably 

 the fifth of the right side. The width at the upper end is 12 mm. The width at the distal end 

 of the fragment, probably about the middle of the length of the costal, has increased to 9 mm. 

 Its thickness is a little more than 3 mm. On the under side of the bone is found the base of a 

 rather well-developt rib-head. 



Testudo laticunea Cope. 



Plate 67, figs. 1, 1; text-figs. 509-515. 



TrsiuJo laticunea, CoPE, Palaeont. Bull. No. 15, 1S73, p. 6; Synop. New Vert. Tert. Colorado, 1873, 

 p. 19; Ann. Rep. Geol. and Geog. Surv. Terrs., 1873 (1874), p. 51 1 ; Vert. Tert. Form. West, 1S84. 

 pp. 762, 765, plate Ixi, figs. I, la. Hay, Bibliog. and Cat. Foss. Vert. N. A., IQ02, p. 451. 



In his original description Professor Cope states that he had in his possession several speci- 

 mens ot this species, hut he does not designate any as the type. In his description ot 1884 one 

 individual in a good state of preservation was used as the basis of the description and was 

 figured. This must now he regarded as the type, especially since the other specimens occur- 

 ring in the Cope collection are very fragmentary. This type is now in the American Museum 

 ot Natural History and hears the number 1 160. All of Cope's specimens were obtained in the 

 Ohgocene beds at the head of Horse Tail Creek, in northeastern Colorado. These deposits 

 belong to the level known as the Oreodon beds. 



The specimen is slightly distorted, somewhat fractured, and some portions are missing. 

 A fracture extends along the midline of the anterior part of the carapace and the elements of 



