TESTUDINID.. 379 



sutures arc so fine that it is not easy to trace them. The nuchal scute is extremely narrow; the 

 supracaudal is divided at the midline. The peripherals over the limbs are considerably flared, 

 but the pygal is nearly perpendicular. The plastron is more concave than in the specimen here 

 first described. Also the lip is more truncate in front. The pectoral scutes are only 48 mm. 

 wide at the midline. The notch in the hinder end of the plastron is 150 mm. wide and 46 mm. 

 deep; beinu, thus much wider than in the specimen here first described. The apices on each 

 side of the notch are rather narrow and pointed. 



No. 5958 of the same museum was collected in 1905. It has a length of 720 mm. The 

 plastral lip has the form shown in the figure of Cope's H . octonanus (Vert. Tert. Form. West, 

 plate xx), having parallel sides and a truncated front. The notch and the apices also resemble 

 those of Cope's H . octonarius. The entoplastron is damaged, so that its form can not be deter- 

 mined. The shell is considerably crusht laterally. 



No. 10082 of the Museum at Princeton University was collected at Smith's Fork, in south- 

 western Wyoming, in 1S7X. It has been regarded as being H. octonarius. Its length is 790 mm. ; 



47""- 



476/.. 



+7 8. 



477- 



FlGS. 476479. /Y,j</r//H;/ 



s corsoni. 



xj. 



479- 



476. Scapula and coracoid. No. 1068 A. M. N. H. a, seen from below; b, seen from in front, cor, coracoid; 



pcor, procoracoid process; tcap, scapula. 



477. Pelvis seen from below. No. 1068 A. M. N. H. r7, ilium; isch, ischium; pub, pubis. 



478. Pelvis seen from left sub'. 



479. Right ilium of large individual. No. 6026 A. M. N. H. 



its width, 635 mm.; its height, 305 mm. The shell is nearly complete. The carapace is convex 

 transversely but rather flat on the middle line. From front to the rear it is convex with the 

 pygal region quite steep. The front and rear are somewhat truncate. All the peripherals 

 are acute-edged. The sutures bounding the neurals are so fine that they have not been 

 determined. The first vertebral scute is 62 mm. wide in front, 135 mm. wide behind, thus 

 differing from that of other specimens in being very narrow in front. The second is 135 mm. 

 wide; the third, 144 mm.; the fourth, 163 mm.; the fifth, 270 mm. The nuchal is 48 mm. 

 long and 36 mm. wide. 



The plastron has a length of about 775 mm. It is very concave, and has probably been 

 that of a male. The lip projects about 80 mm. beyond the front of the carapace. It is large 

 and of rather unusual form. The width at the base is 1 13 mm. but it expands toward the front 



