EMYDID&. 33! 
present are a little narrower, as are also the vertebral scutes. The greatest thickness of the 
nuchal bone is 16 mm. The ninth peripheral is 48 mm. high, 35 mm. wide at the free border 
and 23 mm. wide at the upper border. Its greatest thickness is 13 mm. ‘This and the other 
hinder peripherals thin out to an acute border. The pygal is missing but the eleventh periph- 
erals show that it had a height of 23 mm. and that its right and left sides were convex. The 
heads of the ribs of these specimens had a diameter of 8 mm. 
The plastron differs in having a slightly narrower anterior lobe, 108 mm., a narrower 
hinder lobe, 117 mm., and a narrower lip, 41 mm. The entoplastron 1 is 38 mm. long and 
50 mm. wide. In both specimens the anterior lobe is very short in proportion to its width, 
being only 67 per cent. thereof. 
The rasoeets in which this species differs from £. wgle are stated under the species just 
named. £. septaria differs in the expanded anterior lobe, in the greatly thickened epiplastral 
bones, and in the contracted lip. The acute or subacute anterior border of the carapace of 
E. ocyrrhoé distinguishes it from &. shaughne sstana. 
E. ocyrrhoé differs from FE. hayden: in having the first vertebral scute much broader in 
front and rapidly narrowing posteriorly. The other scutes are as broad as long or nearly so; 
while in E. hayden: they are a aueh longer than broad. FE. stevensonianaisa relatiy ely narrower 
shell, the width being only a little over two-thirds of the length; and more pointed in front and 
behind. The anterior border of E. stevensoniana is more acute than in E. ocyrrhoé and the 
suture between the first and second peripherals is 14 mm. thick, instead of 16.5 mm. The 
epiplastral lips of the two species are different. Comparisons with F. cyane are to be found 
under the latter species. 
Echmatemys egle sp. nov. 
Figs. 436-441. 
‘Two specimens represent at present this species. “These were obtained in the Bridger beds, 
near Bridger, Wyoming, in 1903. Of these, one, No. 5909 of the American Museum of Natural 
History, is made the type. The locality where obtained is the western portion of Grizzly Buttes 
and the level is the lower portion of horizon B. 
The specimen is represented by the complete plastron, the anterior 5 pairs of costal plates, 
the sixth costal plate of the right side, and a few peripherals. “The nuchal bone is missing. 
An estimate based on the plastron makes it probable that the carapace had a length of 
330 mm. The surface is smooth, except for some longitudinal striations on the neural bones. 
The sulci bounding the epidermal scutes are rather deeply and uniformly imprest. The tables 
below give the dimensions of the neurals and of the vertebral scutes, so far as presented. 
There is little difference as respects 
width between the proximal and the 
distal ends of the costal plates. 
Width Greatest The first right peripheral is repre- 
in front.| width. sented by that portion in front of the 
costo-marginal sulcus. — Its free border 
Dimensions of neurals. Dimensions of vertebrals. 
No. Length. Width. No. Length. 
: - i. : 66 - ae is acute at the end next the nuchal bone 
3 34 28 2 68 40 66 but rather obtuse at the end next to the 
a 3° 27 4 ae 45 70 second peripheral. The extent of the 
2 = i free border is 38 mm. The greatest 
height of the second marginal scute was 
about 29 mm. The greatest thickness 
of the bone is 12 mm. A part of the right third peripheral is present and will be referred to 
below. The fifth peripheral 1 is present and shows an angular ridge, along which the upper side 
of the shell past abruptly into the lower side. This peripheral rises abor: e the ridge mentioned 
a distance of 35 mm. and it has a width of 40 mm. The seventh peripheral has a length of 
40 mm. along the free border. Its upper border is broken away. The maximum thickness 
of the end articulating with the eighth is 13 mm., but it may have suffered some compression. 
The eighth peripheral measures 33 mm. along the free border and it rises to a height of 45 mm. 
The vertebral scutes are broad and urn-shaped, quite like those of E. naomr. The table 
above gives the dimensions. 
