EMYDID. 307 
hypoplastron having a length of 73 mm. The superior beveled border is 12 mm. wide. At the 
inner border of this surface the bone is 12 mm. thick. Beyond the bevel the bone thins some- 
what. Near the hypoxiphiplastral suture a groove develops just inside the beveled surface. 
On the lower surface of the bone is seen the broad and deeply sunken abdomino-femoral 
sulcus, which crosses at a distance of 40 mm. behind the anterior border of the bone. The 
median longitudinal sulcus also has been broad and deep. There has been a large inguinal 
scute, part of which lay on the hypoplastron. 
The xiphiplastron has a length of 44 mm. on the midline. Posteriorly there was a notch 
about 35 mm. wide and 10 mm. deep. The superior beveled surface (fig. 390, upper view and 
section at hypoxiphiplastral suture) is separated from that beyond it by a sharp groove. The 
greatest thickness of the bone, 11 mm., is at the summit of the bevel, but for some distance 
it diminishes little. At the midline it has become reduced to about 7mm. The femoral 
scutes measured 50 mm. along the midline; the anals, 25 mm. The femoro-anal sulci are 
deep and wide. 
No. 1119 furnishes, together with unimportant parts, a portion of the epiplastron, 
including the lip. Seen from above, it resembles greatly the one figured by Cope (his plate 
jae 391. 
Fics. 389-391.—Echmatemys euthneta. Costal and plastral bones. 
389. Inner surface of right first costal. <1. Specimen in A.M.N.H. Shows scar for axillary buttress. 
390. Portion of hinder lobe, upper surface, with section of free border. 1. No. 1176 A.M.N.H. 
391. Restoration of plastron. Mostly froin Nos. 1176 and 1182 A. M.N.H. 
xviii, fig. 41a). Seen from below, it is observed that the gular scutes could have extended 
backward hardly more than half-way to the entoplastron. The lip must have been at least 
>2 mm. wide. The whole free border of the bone was obtuse. The superior horn-covered 
surface is convex. Laterally the upper surface of the lip 1s swollen, and is about 7.5 mm. thick; 
but at the midline the thickness 1s reduced to 4mm. The individual was a smaller one than 
either of those just described. A fragment of a fifth or sixth costal is thickened on one side for 
articulation with the sixth or fifth costal and has an articular surface for the inguinal buttress. 
A peripheral and some fragments of costals show that the sulci were rather deeply imprest. 
Lot No. 1174 contains many fragments of more than one individual, possibly of more than 
a single species. Fragments of the fifth and sixth costals appear to indicate that the inguinal 
buttresses were articulated principally with the sixth costal. 
Fig. 391 presents a restoration of the plastron from the various bones described. The 
epiplastral lip is taken from Cope’s figure. 
After the preceding descriptions and figures had been prepared 3 additional specimens of 
this species arrived at the American Museum of Natural History. These were collected in 
1906 by the museum’s expedition sent into the deposits of the Wasatch in Wyoming. They 
were all obtained on Bitter Creek, within about 20 miles of Black Buttes, where Cope obtained 
