272 0. P. Hay — Fossil Turtles in the Marsh Collection. 



The upper portion of the shell and one side of it are some- 

 what damaged. The length of the carapace is 530 mm ; the 

 greatest breadth was at least 440 mm . In form the shell was 

 rather high and vaulted. Over the limbs the peripheral bones 

 are considerably flared upward. The posterior border is 

 rounded and scalloped. The free borders of all the periph- 

 erals have acute edges. The form and dimensions of many 

 of the neurals cannot be determined. There appear to have 

 been three suprapygals, the penultimate of which is bifurcate, 

 as in the species of Testudo. The anterior four or five costal 

 plates are alternately narrow and wide, but the proximal and 

 the distal ends of each are of about the same width, thus differ- 

 ing from the costals of Testudo. 



The peripheral bones, conspicuously those over the bridges, 

 are much higher than those in the Bridger species, H. corsoni. 

 They rise about 90 mm above the slight carina which joins the 

 third with the seventh peripheral. The sulci which bound the 

 epidermal scutes are narrow and shallow, but they run in 

 rather deep grooves in the bones. There are two very distinct 

 supracaudal scutes, a right and a left. 



The plastron has about the same length as the carapace. 

 There is a distinct lip in front. The rear of the plastron is 

 deeply notched. The antero-posterior extent of the pectoral 

 scutes is considerably greater than in H. corsoni. 



The large peripherals and the broad pectoral scutes espe- 

 cially distinguish this species from those of Hadrianus hitherto 

 described. 



Professor Cope has referred some remains of this genus from 

 the Wasatch of New Mexico to H. corsoni, but his specimens 

 were too fragmentary for accurate determination. 



Hadrianus majuscidics is interesting because of its being 

 the oldest known member of the Chersites, or Testudinidse. 



Testudo brontops Marsh. 

 Text-figures 6, 7. 



Testudo brontops Marsh, 0. C, this Journal (3), xl, 1890, p. 179, pi. viii ; 

 Vert. Foss. Denver Basin, in Mon. U. S. Geol. Snrv., xxvii, 1897, pp. 523, 

 527, figs. 95, 96. Dana, J. D., Manual Geol., 1896, p. 901, fig. 1516. Hay, 

 0. P., Bibliog, and Cat. Foss. Vert. N. A., 1902, p. 451. 



This species has already been briefly described by Professor 

 O. C. Marsh, as cited. The writer has been enabled to study 

 with some care this fine specimen, and here presents diagram- 

 matic figures illustrating the structure of the carapace and the 

 plastron. The structure has been somewhat obscured by crush- 

 ing, especially along the midline of the carapace. 



The length of the carapace is 711 mm ; the greatest breadth 

 is 651 mm . " The carapace is truncated in front and broadly 



