KMYIMDA). 



37 



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, 1 1 mm., is at the summit of the bevel, but for some distance 

 it diminishes little. At the midline it has become reduced to about 7 mm. 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 



389- 



FIGS. 389-391. Echmatemys euthneta. Costal and plastral bones. 



389. Inner surface of right first costal. X I. Specimen in A. M. N. H. Shows scar for axillary buttress. 



390. Portion of hinder lobe, upper surface, with section of free border. XL No. 1176 A.M.N. H. 



391. Restoration of plastron. Mostly from Nos. 1176 and 1181 A.M.N.H. 



xviii, fig. 410)- 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 

 22 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 is swollen, and is about 7.5 mm. thick; 

 but at the midline the thickness is reduced to 4 mm. 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. 1 174 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 



