154 MEMOIRS OF THE CARNEGIE MUSEUM 



The vertebral scutes are longer than wide, their dimensions are given in the 



table. 



Dimensions of Vertebral Scutes. 



No. Length. Width. 



1 64 100 



2 74 62 



3 66 63 



4 68 57 



5 66 116 



The costal scutes are wide, their outer ends joining the marginals at the costo- 

 peripheral suture. The costo-marginal sulcus appears to follow closely the course 

 of the costo-peripheral suture. The humero-pectoral sulcus touches the ento- 

 plastron, but does not cross it. 



The supracaudal scute is divided as in Hadrianus. 



A comparison of the type of the present species with the upper Eocene tortoise, 

 Testudo ammon Andrews, from the Fayum deposits of Egypt, shows some striking 

 resemblances. Both Testudo uintensis and T. amnion are distinguished from all 

 other species of the genus by the octagonal shape of the second and sixth neurals, 

 whereas the usual arrangement is for the second and fourth neurals to be octagonal. 

 Both types agree in having seven neurals, although other specimens referred to 

 T. anifnon by Andrews have the normal number of eight, and it may be found that 

 there is a similar variation in the present species. 



Hay^ comments upon Testudo ammon as follows: "Dr. A.[C]E.[W] Andrews 

 (Surv. Dept., Pub. Works Ministry, Geol. Survey, Egypt, 1903; Tert. Vert. Fayum, 

 Egypt, 1906, p. 278, pi. 24) has described a land-tortoise from the Upper Eocene of 

 Egypt to which he has given the name Testudo ammon. If a true Testudo, it is the 

 oldest known. The published figures show that the neurals are variable in form, 

 but the relationships to typical Testudo are so lose that it may be accepted as 

 belonging to this genus. In some respects it appears to be intermediate between 

 Testudo and Hadrianus." 



The above remarks would apply equally well to the species here described. 

 Up to this time the oldest known Testudo found in North America is from the 

 Lower Oligocene. Two species having been described, Testudo brontops Marsh, 

 and T. exornata Lambe. 



If, as has been inferred, Testudo has derived its ancestry from Hadrianus, the 

 intermediate characters observed in the present specimen are fully in accord with 

 its geological position. The axillary and inguinal buttresses rising but little above 



* " Fossil Turtles of North America," 1908, p. 368. 



