452 



FOSSIL TURTLES OK NORTH AMERICA. 



a sharp carma passes backward over the bridge to the tree border behind the inguinal notch. 

 Possibly the acuteness of this has been accentuated by crushing. 



The plastron projects considerably in front of the carapace. This does not appear to be 

 due to any crushing, {or the hinder end of the plastron approaches closely the border of the 

 carapace. 



The length of the carapace is 305 mm.; its width, 280 mm. All the free borders are acute. 

 The nuchal has a length of 57 mm., a maximum width of 67 mm., and a width of 43 mm. along 

 the free border. The first neural is oval, the second and fourth octagonal; the third, fifth, and 

 eighth are 4-sided; the sixth and the seventh, hexagonal. The table shows their dimensions. 



The costal plates are alternately wide and narrow at their proximal ends and narrow and 

 wide at their distal ends. The widths are given in the table above. 



The nuchal scute is 15 mm. long and 13 mm. wide. The dimensions of the vertebrals are 

 herewith shown in tabular form. 



The plastron has a length of 325 mm., being thus longer than the carapace. The anterior 

 lobe is 100 mm. long and 148 mm. wide at the base. The epiplastral lip is 70 mm. wide at the 

 ends of the gulo-humeral sulci and it projects beyond these a distance of 28 mm. The free 

 borders of the lobe, including the lip, are acute. The anterior border of the lip is notcht. 

 The thickening of the lip is continued backward a distance of 45 mm. from the front; it then 

 drops off suddenly, forming an escarpment, which is somewhat excavated beneath. At the hyo- 

 epiplastral suture the width of the superior horn-covered surface is 27 mm. The entoplastron 

 is 61 mm. long and 58 mm. wide. The bridge has a width of 150 mm. 



The hinder lobe is 55 mm. long at the midline, 70 mm. total, and has a width of 155 mm. 

 at the base. Median notch 15 mm. deep and 55 mm. wide. Near the inguinal notch the free 

 border of the lobe is about 17 mm. thick; more posteriorly it becomes thin and finally acute. 



The gular scutes are 60 mm. long in the midline. The humerals occupy 54 mm. of the 

 midline; the pectorals, 24 mm.; the abdominals, 95 mm.; the femorals, 40 mm.; the anals, 

 33 mm. The axillary and inguinal scutes are present, but small. 



No. 1536 of the Carnegie Museum is a nearly complete shell, smaller than the preceding. 

 It is referred to this species. It presents the difference of having a smaller epiplastral lip. 



No. 1570 of the Carnegie Museum is also referred to the present species. It was obtained 

 in 1902, by Mr. Earl Douglass, at Cold Spring, Montana, in what the discoverer regards as 

 Upper Loup Fork beds. 



The hinder parts of both carapace and plastron are wanting. The epiplastral lip does not 

 project so much in front of the carapace as in the type, but this may be due to some distortion. 

 The entoplastron is 52 mm. long and 60 mm. wide, differing thus somewhat from that of the 

 type, whose entoplastron is longer than wide. Pectoral scutes 28 mm. wide at midline. 



The surfaces of this shell and those of the type are sculptured by the growth lines of the 

 epidermal scutes. 



This species differs from T. jarri in having the first vertebral scute much less expanded, in 

 having the opposite ends of the costals more narrowed and more widened, and the epiplastral 

 lip more strongly developt. It differs from T . vaga in having a more projecting epiplastral 

 lip, a differently shaped entoplastron and pectoral scutes narrower at midline. 



This species is dedicated to Dr. W. J. Holland, director of the Carnegie Museum, Pitts- 

 burg, Pennsylvania. 



