JO6 FOSSIL TURTLES OK NORTH AMKRICA. 



This is one of the two species of emyd turtles described by Professor Cope from the Green 

 River beds in the region of Black Buttes, the other species being E. megaulax. Emys euthneta 

 is said to have been represented by numerous specimens and to have been abundant in the 

 red beds which lie between those identified as belonging to the Green River and the Bndger 

 epochs at Black Buttes. The figured bones of the species are in the National Museum at 

 Washington. They have the catalog number 4125. 



In the American Museum there are three lots, parts of the Cope collection, which appear 

 to belong to this species. The parts which were figured by Cope were 3 neurals, 4 peripherals, 

 I epiplastron, and a part of I xiphiplastron. All these, it is stated, were found together and 

 were supposed to belong to a single individual. The neurals displayed no dorsal keel, the 

 scutal sulci were not deeply imprest, and the surfaces of the carapacial bones were smooth. 

 The length of the carapace of this individual must have been about 190 mm., the three neurals 

 taken together measuring 49 mm. One neural, probably the third (Cope's fig. 34), had a 

 length of 19 mm. and a width of 15.5 mm., and a thickness of 4 mm. The neurals were not so 

 wide in proportion to their length as in E. megaulax. The peripherals resemble those of E. 

 megaulax, but they were not so deeply imprest by the sulci. The peripheral represented by 

 Cope's fig. 37 is apparently an anterior second. It is 8 mm. thick where it joined the third. 

 Cope's fig. 38 appears to represent the ninth peripheral of the right side, while his fig. 40 shows 

 probably the eighth of the left side. The border which articulated with the seventh is 7 mm. 

 thick; that which articulated with the ninth is 6 mm. thick. Cope's figure of the epiplastron 

 shows correctly that the lip projected abruptly for a short distance, and was little, if at all, 

 notcht at the midline. It is rounded off both above and below and has the free border obtuse. 

 Its greatest thickness is 6 mm. It is doubtful how near the midline the fragment approacht, 

 so that the width of the lip is uncertain. The hinder lobe is broadly notcht and the beveled 

 surface on the upper side is relatively narrow. The thickness of the border is 5 mm. anteriorly. 

 Here the free edge is- obtuse but posteriorly it becomes acute. 



In the Cope collection of fossil reptiles, in the American Museum of Natural History, 

 there are four lots of bones which are labeled by Cope as having come from the "red beds" 

 of Black Buttes and were regarded by him as belonging to his Emys euthneta. These bear the 

 catalog numbers 1119, 1174, 1176, and 1182. Nos. 1176 and 1182 together present nearly 

 the whole of the plastron, except the epiplastron and the entoplastron. No. 1182 furnishes 

 most of the hyoplastron of the right side and most of the hypoplastron of the left side. These 

 bones are relatively thin. 



The plastron had a total length of nearly 240 mm. At the crossing of the median longi- 

 tudinal suture and the hyohypoplastral suture the thickness is 7 mm. On account of some 

 missing fragments, the length of the hyoplastron can not be exactly determined. The anterior 

 lobe has a width of about 120 mm. The free border of the epiplastral process is acute, but 

 soon the bone thickens to 8 mm. At the hyoepiplastral suture the beveled surface on the upper 

 side is 10 mm. wide. No groove separates it from the surface beyond. The humero-pectoral 

 sulcus, deeply sunken, crosses the free border of the bone 14 mm. behind the suture just 

 mentioned. It appears almost certain that this sulcus did not touch the entoplastron. A 

 deeply imprest sulcus cut off an axillary scute, only a part of which was situated on the hyo- 

 plastron. The pectoro-abdominal sulcus crosses the bone at a distance of 19 mm. in front of 

 the hyohypoplastral suture, measured at the midline; measured at the free border of the bone 

 the distance is 30 mm. This sulcus is narrow and shallow. On the upper side of the bone, 

 on the outer two-fifths, a strong axillary buttress arises for articulation with the first costal. 



The hypoplastron has a length of 70 mm. The width of the hinder lobe was close to 105 

 mm. The free border has an acute edge. The superior beveled surface has a width of 10 mm. 

 at the hypoxiphiplastral suture. No groove intervenes between this surface and that beyond. 

 At a distance of 20 mm. from the free border the thickness of the bone is 8 mm. The inguinal 

 buttress rises from the upper surface of this bone at a line less than half the distance from 

 the free border to the midline. The abdominal scutes of this individual had a length of about 

 58 mm. A fragment of the first costal (fig. 389) shows that the axillary buttress of this turtle 

 ascended a distance of 20 mm. on the inner surface of the costal. 



Specimen No. 1176 (plate 46, fig. i) presents the nearly complete hypoplastron and the 

 complete xiphiplastron. The individual was only slightly smaller than the preceding, the 



