2 3 



FOSSIL TURTLES OF NORTH AMERICA. 



some portions of the neurals and the contiguous borders of the right third and fourth costal 

 plates are wanting. 



The carapace (plate 33; text-fig. 288) is deprest, due probably in some degree to pressure. 

 The anterior border is excavated over the neck, broadly rounded behind. Behind the ingui- 

 nal notches the borders are somewhat flared upward. 



The length of the carapace from the bottom of the notch in front to the rear, measured in 

 a straight line, is 715 mm.; the breadth is very close to 585 mm. The anterior notch is 22 mm. 

 deep. The free border in this notch is about 25 mm. thick. On each side of the midline the 

 border thins rapidly and soon forms an acute edge, which continues to the axillary notch. 

 Behind the inguinal notches the free edges are acute. 



The nuchal bone measures 85 mm. along the midline; its width is 145 mm. The first 

 neural was about 80 mm. long and 60 mm. wide behind. The second neural is oval, 68 mm. 

 long, 40 mm. .wide. The third is broadest in front, 80 mm. long, 50 mm. wide. The fourth 

 neural is wanting; the fifth is defective. The sixth is 70 mm. long, 50 mm. wide. The seventh 

 and eighth are small and irregular in form. There is a small first suprapygal. The second 

 is bifurcate, as in Testudo. It measures along the midline 60 mm.; its lateral extent is 170 



mm. The third suprapygal is 72 mm. along the midline and 135 



mm. wide. The pygal bone is 52 mm. high and 75 mm. wide. 

 The tenth peripheral bone is 85 mm. along the free border and 

 102 mm. high. There are II pairs of peripherals. 



The nuchal scute is small, about 25 mm. long and 15 mm. 

 wide. The first vertebral scute is unsymmetrical. On the left 

 side the anterior border extends IOO mm. from the midline; on the 

 right side apparently only 60 mm. The left appears to be the nor- 

 mal side. The table herewith gives dimensions of the vertebrals. 



It will be observed that, with the exception of the first and the last, the vertebrals are 

 considerably longer than wide. The costal scutes are large. The second has a longitudinal 

 extent of 1 60 mm. and a height of 240 mm. They extend far below the costo-peripheral 

 sutures. Of the marginal scutes there are 12 pairs. The second extends from the free border 

 42 mm. to the first vertebral scute. The third has a height of 60 mm.; the ninth a height of 

 60 mm.; the twelfth, a height of 75 mm. 



On the lower side of the first and second peripherals the portion covered by the horny 

 scutes is about 50 mm. wide. Toward the nuchal bone and the axillary notch this narrows 

 greatly. Behind the inguinal notches the horn-covered surface on the lower side of the periph- 

 erals is about 45 mm. wide to the midline behind. 



The plastron (plate 33; text-fig. 289) has a total length of 660 mm. The lobes are short, 

 the bridges wide. The length of the anterior lobe, to a line joining the bottoms of the axillary 

 notches, is 160 mm. The breadth, taken from the inner border of one axillary notch to the 

 other, is 330 mm. 



Anteriorly the lobe ends in a beak as prominent as that of many species of Testudo. 

 From the anterior end of one gulo-humeral sulcus to the other, the width is 95 mm. The beak 

 extends 42 mm. in front of this. On the lower surface the beak is nearly flat, but toward the 

 front it develops a broad median channel. Laterally the borders of the beak, like those of 

 the whole anterior lobe, are subacute. From this subacute. edge the bone rises abruptly and 

 nearly perpendicularly, finally rounding off into the convex upper surface of the beak. The 

 maximum thickness of the bone is 50 mm. On the upper side of the beak the ornamented 

 surface extends back about 55 mm. From the sides of the beak this sculptured surface narrows 

 toward the axillary notch. At the junction of the epiplastron with the hyoplastron the bone 

 is 35 mm. thick. The median portions of the anterior lobe are much thinner. 



The entoplastron is short but very wide. Its fore-and-aft extent is no mm., the breadth, 

 145 mm. The form is shown in the figures. 



The bridges are about 370 mm. wide. The hinder lobe has a length of 145 mm. and a 

 width of 300 mm. At the borders, for some distance behind the inguinal notches, the bone 

 turns abruptly and perpendicularly upward to the summit of a ridge running backward from 

 the inguinal notch. From the summit of this ridge the bone slopes rapidly downward to the 

 central portion of the lobe. At the hypoxiphiplastral suture the ridge is 50 mm. above the 



