434 



FOSSIL TURTLES OF NORTH AMERICA. 



lobe is 470 mm., its length 230 mm. The anterior lip projects well beyond the crossing of the 

 gular sulci. It does not pass beyond the carapace; whereas, in T. osborniana the lip projects 

 beyond the carapace about 80 mm. The lip is 185 mm. wide at its base and nearly as wide in 

 front. It is nearly flat below, convex above, and thickens backward on the upper surface to a 

 thickness of 60 mm. The posterior face of this thickened portion is somewhat excavated. 

 The whole free border of the anterior lobe is acute. 



The posterior lobe has a width of 475 mm. and a length of 200 mm. The notch is broad 

 and shallow, its width being 165 mm., its depth only 30 mm. At the inguinal notch the border 

 of the hinder lobe presents a wall 85 mm. high, with a perpendicular outer face and a sloping 

 inner one. The wall diminishes rapidly in height backward, so that the thickness of the apices 



570. 57i- 



FIGS. 570 AND 571. TestuJo impensa. Carapace and plastron of type. X J- 

 570. Carapace. 571. Plastron. 



of the xiphiplastra is only 34 mm. The structure of this region is greatly like that of T. osborn- 

 iana. The entoplastron is rhombic, 175 mm. on the midline, 230 mm. in transverse extent. 

 The suture between the two hyoplastra is 160 mm. long; that between the hypoplastra, 175 

 mm.; that between the xiphiplastra, 145 mm. 



The first vertebral scute is 250 mm. wide in front. The second is 180 mm. wide; the 

 third is 137 mm. long and 200 mm. wide; the fourth, 166 mm. wide; the fifth, 210 mm. long 

 and 300 mm. wide. The gular scutes lap over on the entoplastron. The humeral scutes join 

 along the midline for 175 mm. The pectoral scutes are very narrow at the midline. only 

 about 15 mm., but their outer ends expand greatly. The abdominal scutes occupy 275 mm. 

 of the midline; the femorals, 75 mm.; the anals, 96 mm. 



The scapula is a large and stout bone. Its upper end, for union with the first costal, 

 extended above the glenoid cavity a distance of 162 mm. Near this upper end the bone is 38 



