68 
FOSSIL TURTLES OF NORTH AMERICA. 
obtained at Church Buttes, in the level known as B. Dr. Leidy’s figure makes the anterior 
lobe of the plastron appear too short and too narrow. The plastron has a total length of 275 
mm. The anterior lobe is 75 mm. long and 70 mm. wide at the base. The bridge has a width 
of 123mm. The hinder lobe is 77 mm. long and 110 mm. wide at the base. The carapace has 
straight line. The surface is uneyen, especially within the areas of the 
a length of 300 mm. ina 
Type of B. No. 
| Werte: affints. A.M. 
bral. 
Length. Width. Length. Width. 
1 50 2 48 
2 73 61 72 
3 73 64 77 
4 6o 63 62 
5 55 75 57 
5973 
Nets 
vertebral scutes. There appear to have been no supernumer- 
ary costal scutes. The dimensions of the vertebrals are given 
in the accompanying table. 
The American Museum expedition of 1903 collected a 
number of specimens which must be referred to this species. 
The most important of these is No. 5973, collected at Grizzly 
Buttes, Wyoming. It furnishes a somewhat damaged shell, 
the skull, lacking the left side and the lower jaw; a portion of 
the shoulder-girdle; the humerus, lacking the distal end; and 
the ulna. The length of the carapace (plate 12) in a straight 
line is 330 mm., to the bottom of the posterior notch, 320 mm.; 
its width, about 315 mm. The bones are thoroly co-ossified 
and the sutures obliterated. The anterior border projects somewhat at the midline. The pos- 
terior border is broad, with a median excavation 60 mm. wide and lateral scallops. 
Fics. 44-48.—-Baéna arenosa. No. 5973 A. M.N. H. 
44. Pelvis seen from left side. 3. 47. Left humerus. X 3. 
45. Left half of pelvis seen from below. 3. 48. Right ulna. 3. 
46. Plastron. >}. 
On each side of the first vertebral there is a small supernumerary costal scute. Along the 
midline there is a narrow ridge and within the areas of the vertebral scutes a number of sym- 
metrically arranged ridges. 
The plastron (plate 13, fig. 1; text-fig. 46) is 287 mm. long. The anterior lobe is 77 mm. 
long; 104 mm. wide at the base; and 77 mm. at the gulo-humeral sulcus. The limits of the 
entoplastron can not be traced. The bridge is 125 mm. wide. By means of the striations on the 
The dimensions of the vertebrals are given in the table above. 
