410 FOSSIL TURTLES OF NORTH AMERICA. 



project beyond the general border of the lobe. It is truncated in front. The distance between 

 the crossings of the gular sulci over the free border is no mm. On the upper side (fig. 530), 

 the lip extends backward 60 mm., thickening until it reaches 36 mm. There is no excavation 

 behind the thickened portion. The suture between the epiplastrals is 65 mm. long. The 

 entoplastron is hexagonal, pointed in front, broad behind. The length along the midline is 

 108 mm.; its greatest breadth is 104 mm. The hinder lobe may be described from Cope's 

 type. In this individual the hinder lobe was 240 mm. wide and 143 mm. long to the ends of 

 the xiphiplastral apices. The notch in the rear was about 76 mm. wide and 37 mm. deep. 

 In the median portion of this lobe the bone is about 15 mm. thick, but at the inguinal notch 

 the thickness is 42 mm. Here the outer face is almost perpendicular, but it at once begins to 

 slope inward and upward and to diminish in height, so that at the apices of the xiphiplastra 

 the face looks upward and the thickness is only 27 mm. On these apices the face is 56 mm. 

 wide. From the inguinal notch backward this face is separated from the remainder of the 

 bone by a rather sharp ridge. This markt the boundary between the skin and the bone 

 covered with horn. In the case of both the specimens furnishing the posterior lobe there is a 

 sharp notch, about 6 mm. deep, at the very apex of the xiphiplastron. 



The gular scutes encroach on the entoplastron. The humero-pectoral sulci pass close behind 

 it. The pectoral scutes are about 20 mm. wide at the midline; the abdominals about 75 mm.; 

 the xiphiplastrals, 50 mm. All of the sulci are narrow, but some are rather deeply imprest. 



A portion of another plastron, No. 1147 (fig. 531), consisting of the left hypoplastron and 

 the left xiphiplastron, has a length of 255 mm. The horn-covered surface on the apex of the 

 xiphiplastron is 74 mm. wide. 



The elements of the right half of the shoulder-girdle are present. The scapula is about 

 105 mm. long and 14 mm. wide at the middle of its length. The coracoid is 75 mm. long, 

 and its median border is 60 mm. long. The scapula and the procoracoid process make a little 

 more than a right angle with each other. 



There are in the American Museum of Natural History portions of 2 shells from the same 

 region as those described above which are referred with some doubt to the same species. 

 They were considerably larger and had thicker bones. Other specimens still, No. 1 146 of the 

 same museum, collected on Old Woman's Creek, Wyoming, in White River deposits, may 

 belong to T ' . amphithorax, but the more characteristic parts are missing. The borders of the 

 hinder lobe are identical in form with those of the type specimen. 



Testudo quadrata Cope. 



Tcit-figs. 532, 533. 



Testudo quadratus, COPE, Vert. Tert. Form. West, 1884, p. 764, plate Ixi, fig. 5. HAY, Bibliog. and Cat. 

 Foss. Vert. N. A., 1902, p. 451. 



This species is based on the lip of a plastron and a portion of a nuchal bone. Notwith- 

 standing the meager nature of these materials, there can be no question regarding the distinct- 

 ness of the species. The remains were collected by Cope in 1873, in the Oreodon beds of the 

 White River deposits, at the head of Horse Tail Creek, in northeastern Colorado. The 

 individual was evidently a large one. The type specimen is in the American Museum of 

 Natural History and bears the number 1149. 



The anterior lip (fig. 532) projected much beyond the general outline of the front lobe. 

 The right and left borders are parallel. The anterior border has crumbled away somewhat, 

 except at a point near the midline; but it was doubtless truncated, with probably a slight 

 notch at the midline. The lateral and probably also the anterior borders were acute. The 

 upper surface is slightly convex, the lower nearly flat. Evidently the lip formed something of 

 an angle with the ascending lower surface of the plastron. The hinder face of the upper 

 part of the lip was not excavated. 



What distinguishes this species from all others of our region is the form of the gular scutes. 

 Instead of extending back on the entoplastron, they end at the base of the lip at a sulcus 

 which runs at right angles with the midline. Each scute is therefore about square. The 

 following are dimensions of this lip: Length of lip from gulo-humeral sulcus, 70 mm.; width 

 of lip at base, 120 mm.; thickness at the base, 29 mm. 



