FOSSIL TURTLES OF NORTH AMERICA. 
WwW 
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1) 
The type, No. 5933, measures, from the front of the plastron to the rear, 280 mm. The 
length of the carapace (fig. 432) is 302 mm. The width in a straight line is 223 mm., thus 
being 74 per cent. of the length. The shell has 
Dimensions of neurals. Dimensions of costal bones. been little, if any, crusht downward, and the 
: ; & : ahaa 
Saar PRT height is now 108 mm. The front is slightly 
No. Length. Width. No. of proxi- of distal incurved in front. The anterior border is sub- 
malend. end. acute, and the anterior peripherals thicken rap- 
idly. The surface of the shell is smooth. 
1 37 24 2 29 35 S 
5 as 38 3 31 26 The neurals are rather broad, having the 
3 30 26 4 25 40 dimensions shown in the table herewith. 
28 25 3 8 : : 
4 > 5 33 The nuchal is 48 mm. long, 37 mm. wide 
5 29 22 6 21 35 ¥ r 
é 21 28 7 19 25 at the free border, and 63 mm. where widest. 
7 18 3 The costal plates behind the first pair are 
8 2 16.5 
differentiated so that the proximal ends are 
alternately narrower and wider, while the distal 
ends are alternately wider and narrower. The dimensions of the costal plates are given in 
the table above. 
The table below shows the dimensions of the peripherals, the vertebral scutes, and 
the marginals. 
The height of the third peripheral is only 44 per cent. of the height of the first costal near 
its hinder border. The width of this costal is 70 per cent. of its height. 
The nuchal has a length of 14 mm. and a width of 13 mm. The vertebral scutes, except 
the first, are of moderate width. 
Dimensions of peripherals. Dimensions of vertebral scutes. Dimensions of marginals. 
Width = Width Width : Length 
No. Height. of free ofupper No. Length.) ante- Se No. Bie leat at fee 
border. border. riorly. width. inifront}/ Height. border. 
I 34 35 17 I 57 80 8o I 14 23 31 
2 32 35 18 2 57 45 61 2 23 26 33 
3 34 37 32 3 61 38 53 3 20 20 33 
6 38 39 37 4 66 4! 58 4 20 22 37 
8 8 36 25 5 50 34 . 7 30 33 37 
8 33 37 36 
The anterior lobe of the plastron (fg. 433) has a length of 76 mm., and a width of 113 mm., 
at the base. The borders continue straight forward to the suture between the hyoplastron and 
the epiplastron, then curve toward the lip. The latter 1s 4g mm. wide, truncated and provided 
with a short stout tooth on each side. It extends as far in front as the border of the nuchal. 
The greatest thickness of the epiplastral bones is 13 mm. The thickening on the upper surface 
(fig. 434) extends backward 24 mm. The horn-covered surface is 18 mm. wide, becoming 
reduced to 16 mm. at the hyoepiplastral suture. The entoplastron is 47 mm. long and 53 mm. 
wide. The anterior buttresses ascend only about one-third the distance from the lower to the 
upper border of the first costals. 
The bridge has a width of 118 mm. The hypoplastrals, in the midline, just behind the 
suture with the hyoplastrals, are 13 mm. thick. This is reduced very little toward the anterior 
and the posterior buttresses. 
The hinder lobe has a length of go mm. and a width of 126 mm. The buttresses are 
broad. The beveled surface (fig. 435) on the upper side of the hinder lobe is of only moderate 
width, 19 mm. at the suture with the xiphiplastral. The posterior notch appears to have been 
rather shallow. 
The gular scutes are 40 mm. long; the humerals, 33 mm.; the pectorals, 48 mm.; the 
abdominals, 73 mm.; the femorals, 38 mm.; the xiphiplastrals, at the midline, 45 mm. The 
axillary scutes are quadrilateral and fail by 15 mm. of extending backward to the fifth marginals. 
The inguinals lack the same distance of reaching to the sixth marginals. 
No. 5954 is of almost exactly the same size as No. 5933, the length of the plastron to the 
hypoxiphiplastral suture being 218mm. It varies in slight degrees from the type. The neurals 
