370 FOSSIL TURTLES OF NORTH AMERICA. 
The entoplastron appears to have been of the same form as in F/, corsoni. Its length is 
80 mm., its width 120 mm. The length of the bridge is 206 mm. 
On account of lateral crushing the width of the posterior lobe can not be accurately 
determined. Its length is 175 mm. It is conspicuously notcht behind, the depth of the notch 
being 45 mm. 
The gular scutes probably overlap slightly the entoplastron, but this is not certain. The 
humero-pectoral sulcus skirts the hinder border of the 
fiwew \ entoplastron. ‘The pectoral scutes have a form quite differ- 
} \ ent from that of Hl. corsoni. They are narrow just 
oN mesiad of the axillary notch, but grow wider as they 
yr \ approach the midline, attaining there a width of 75 mm. 
At the midline the abdominals have a fore-and-aft extent 
\ of 140 mm., the femorals 80 mm., the anals about 55 mm. 
The sulci of the plastron are rather narrow and shallow, but 
those of the bridge lie in deep grooves. 
This species differs from H. corsonz in several respects. 
The most conspicuous is perhaps the height of the periph- 
erals, especially those above the bridges. The form and 
width of the pectoral scutes too is distinctive. The bridge 
appears to be shorter in comparison with the length of 
the anterior lobe. The hinder borders of the carapace 
are more scallopt than in H. corsont. 
Prof. E. D. Cope referred some remains of Hadri- 
anus from the Wasatch of New Mexico to H. corsoni; while 
other remains he regarded as a distinct species, which, 
however, he did not name. His specimens appear to be 
lost. It is doubtful whether any of them belonged to the 
Bridger species. 
Hadrianus majusculus is interesting ‘because of the fact that it is the oldest-known repre- 
sentative of the family Testudinide. 
Fic. 472.—Hadrianus mayusculus. 
Plastron of type. > %. 
Hadrianus corsoni (Leidy). 
Plates 60, 61; text-figs. 473-479. 
Testudo corsont, Lewy, Proc. Acad. Nat. Sci. Phila. 1871, p. 154; U. S. Geol. Surv. Montana, etc., 
1872, p. 366; Proc. Acad. Nat. Sci. ees 1872, p. 268; Contrib. Extinct Vert. Fauna West. Terrs., 
1873, pp- 132, 339, plate xi, figs. 1,2; plate xv, fg. 7; plate xxix, figs. 2-4; plate xxx, figs. tas 
Emys cartert, Leipy, Proc. Mead, Nat. Ser. Phila. 1871, p. 228; Amer: Jour. Sci., (3) 1, 1871, p. ; 
U. S. Geol. Surv. Mont., etc., 1872, p. 367; Contrib. Ext. Vert. Fauna West. Terrs., 1873, ne XL. 
T estudo hadrianus, Cope, Paleont. Bull. No. 1, 1872; Proc. Amer. Philos. Soc., xu, 1873, p- 463. 
Hadrianus quadratus, Cope, Proc. Amer. Philos. Bist xil, 1873, p. 468. 
Hadrianus octonarius, Copr, Paleont. Bull..No. 2, 1872; Proc. Amer. Philos. Soc., xu, 1873, p. 468; 
U.S. Geol. Sury. ‘Teris:, 6th. Ann. Rept., 1872 (1873), p. 630; Amer. Naturalist, xv1, 1882, p. 992, 
figs. 11-13; Vert. Tert. Form. West. 1884, p. 140, plate xx, figs. I-4.—OsBorn, ScoTT, and SPEIR, 
Pal. Rept. Princeton Sci. Exped. 1877, p.g5.—Hay, Bibliog. and GaeyRoss. Vert. N. A., 1902, p. 450. 
Hadrianus corsoni, Core, U. S. Geol. Surv. Terrs., 6th. Ann. “Rept., 1872 (1873), p. 631; Syst. Cat. 
Vert. Eocene N. Mex., 1873, p- 36; ?Ann. Rept: Chief Engineers, Explor. W. tooth Merid., 1875, 
p- 1016 (of separata, p. 96); ?Wheeler’s Rept. U.S. Geog. Surv. W. 1ooth Merid., 1v, 1877, p. 58, 
plate xxiv, figs. 36, 37; Amer. Naturalist, xvi, 1882, p. 9g2; Vert. Tert. Form. West, 1884, p. 141.— 
Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 450; Amer. Geologist, xxXv, 1905, p- 333- 
This species was based on the anterior portion of a plastron which was discovered by Dr. 
Corson at the Grizzly Buttes, about 15 miles south of east of Fort Bridger, Wyoming, and 
which was sent for study to Dr. Leidy. This was figured by the latter icon in his Contribu- 
tions to the Extinct Fauna of the Western Territories, plate xv, hg. 7, and is in the Academy 
of Natural Science, at Philadelphia. In 1871 Dr. Leidy made a trip to Fort Bridger and 
obtained a number of specimens of the same species, and these added much to the knowledge of 
the animal. Among the remains secured was a large plastron which, on account of post- 
mortem injury to the lip, Dr. Leidy did not recognize and which he made the type of the species 
