314 FOSSIL TURTLES OF NORTH AMERICA. 
Dr. Leidy’s type of the present species was found near Fort Bridger, Wyoming, and 
probably in the level now known as B. It belongs to the U.S. National Museum and has the 
number tog. It consists of the anterior part of the carapace. This was figured by Leidy, 
but the peripherals were omitted, having been found afterwards. 
These have been included in fig. 404. 
pe eee) See From the front of the nuchal to the anterior border of the 
seventh neural is 255 mm. The length of the nuchal is 57 mm.; 
I Be ge the width in front, 60 mm.; the greatest width, 75 mm. The 
; a a fourth neural 1s octagonal. The table shows the dimensions of 
4 3 27 the neurals. 
2 The first peripheral measures 50 mm. along the free border. 
The height is 48 mm. The sulcus between the costal and the 
marginal scutes runs about 20 mm. below the upper border. The 
dimensions of the vertebral scutes are given in the table below. 
No. 1067 of the American Museum was found by Cope in the Bridger region. Fig. 
405 shows the carapace; fig. 407, the plastron seen from below; while plate 47, fig. 2, 
shows the plastron from above. This figure is to be 
Width. compared with fig. 1 of the same plate, E. wyomingensis, 
Vertebral. Length. = especially as to the origins of the axillary and inguinal 
In front. | Greatest. huttresses: 7 
In the American Museum is found the specimen 
I 73 87 87 Fi ‘ , “ 
Le ‘0 4 described by Cope as belonging to this species. Its 
3 80 37 53 number is 1072. It resembles the specimen to be 
4 5e 95 described below, except that the rib-heads are broader, 
having the diameter of 12 mm. where they leave the 
carapace. The individual was slightly larger than No. 1067, but not enough larger to 
account for the difference. 
No. 1071 of the American Museum is a part of the Cope collection, but the exact locality 
where it was found is not known. It came, however, from the Fort Bridger region. It belonged 
to an individual whose shell was about 250 mm. long. The bones and sutures have an appear- 
ance of immaturity. The features that characterize the specimens already mentioned hold 
good here. The form was convex, as described by Cope. The fourth neural is octagonal, the 
fifth quadrate. The vertebral scutes are proportionally wider than in the type, but this may 
be due to less advanct age. Over the bridge the costo-marginal sulci ran very close to the 
costo-peripheral sutures. On the costals are seen concentric grooves, which show the growth of 
the horny scutes. On the first costal bone these are at an average distance apart of 7 mm., 
fact indicating rather rapid growth. The plastron 1 is not ereatly thickened, the front of the 
hypoplastron being 11mm. The lip has a notch in front, w eich cuts off a tooth on each side. 
Behind this tooth the thickness 1s 11 mm. 
Another specimen in the American Museum of Natural History which is referred to £. 
haydeni is numbered 3943. It consists of a shell lacking only some of the hinder peripherals. 
It was collected in 1904, by Mr. Walter Granger, in the Bridger Eocene beds, about the middle 
of the length of Cottonw ood Creek, and therefore belongs to the lower portion of horizon B. 
The shell is crusht laterally, so that the height is probably greater than in life, being now 182 
mm. The length of the plastron is 370 mm., from which it is estimated that the carapace had 
originally a length of more than 400 mm. ‘The present width is 262 mm. 
: The carapace (fig. 407) is smooth and the sulci are moder- 
ately imprest. On the last neural and the suprapygals there is a 
trace of a low keel. The nuchal bone has a length of 69 mm., a 
width of 56 mm. in front, and a maximum width of about 80 
Neural. Length. Width. 
ry : mm. The neurals are broad. Two of these are octagonal, the 
3 46 26 second and the fourth, but this is believed to be only an individual 
fl . 31 variation. In the American Museum of Natural History there is 
6 29 ae a specimen of Chelydra serpentina in which the same neurals are 
: a2 39 octagonal. The table herewith presents the dimensions of the 
§ 25 3 
> 
neurals of 3943. 
