35 FOSSIL TURTLES OF NORTH AMERICA. 



number of longitudinal grooves, which mark the growth of the scutes. The deepest ones are 

 from 5 to 7 mm. apart and appear to indicate the yearly increase in size. On each peripheral 

 behind the bridge we find in front of the sulcus crossing it some strong grooves parallel with 

 the free border of the shell; behind the sulcus, some more delicate grooves more nearly parallel 

 with the axis of the shell. 



The length of the plastron (plate 55, fig. 2; text-fig. 452), from the outer anterior angle of 

 the epiplastron to the extremity of the xiphiplastron, is 165 mm. In the midline, from the 

 hinder border of the entoplastron to the notch in the rear, the length is 142 mm. The width of 

 the anterior lobe at the base is 91 mm. The entoplastron had a width of 33 mm. 



The bridge has a width of 69 mm. It rises rapidly from the bottom of the plastron. 



The hinder plastral lobe has a length ot 75 mm. and a width of 90 mm. at the base. Near 

 the suture between the hypoplastra and the xiphiplastra the width is 96 mm. At the end of the 

 femoro-anal sulcus there is only a slight notch. The free margins of the plastral lobes, so far 

 as preserved, are acute. The extremities of the xiphiplastral bones are rounded and slightly 

 dentated. 



The humero-pectoral sulcus crosses the plastron behind the entoplastron The pectoral 

 scutes have a width at the midline of 27 mm.; the abdominals, a width of 22 mm.; the anals, 

 a width of 40 mm. There are large axillary and inguinal scutes. 



The lower surface of the plastron is delicately grooved longitudinally. 



Professor Cope mentions the presence of portions of the skull; but there is little more than 

 the left quadrate. It presents no difference when compared with that of T . rugosa. 



The shoulder-girdle and the limb bones appear to resemble essentially those of the living 

 species just mentioned. 



Trachemys euglypha (Leidy). 



Plate 54, fig. 3. 



Emys euglypha, Leidy, Proc. Acad. Nat. Sci. Phila. 1889, p. 97; Trans. Wagner Free Instit., n, 1889, 

 p. 27, plate iv, fig. I. Hay, Bibliog. and Cat. loss. Vert. N. A., 1902, p. 447. 



The present species was based on a single bone, the nuchal, ot a turtle found in the Peace 

 Creek beds, Florida. Dr. W. H. Dall, of the U. S. Geological Survey, has examined these 

 deposits and pronounct that bed, about 2 feet in thickness, from which vertebrate remains 

 have been obtained, to be ot older Pliocene age. However, since from that bed Dr. Leidy has 

 described vertebrates belonging to various epochs, from the Miocene to the present, the correct- 

 ness of the determination is in question. The type of the species here described belongs to 

 the Wagner Free Institute, Philadelphia, but the writer has not been able to find it there. 



Dr. Leidy has referred his species to the genus Emys; but it can not belong there as that 

 genus is understood at present. The nuchal resembles closely that of a specimen of Trachemys 

 scripta now in the American Museum of Natural History. From this, however, it differs 

 specifically. The length of the bone at the midline is 58 mm. The total length of the carapace 

 of the specimen of T. scripta just mentioned, the length of whose nuchal is 50 mm., is 210 mm. 

 We may therefore conclude that the carapace of Dr. Leidy's type had a length of about 

 290 mm. The width ot the front of the nuchal is ^y mm., the greatest width y^ mm. This 

 border is deeply notcht, but the bottom of the notch is divided by the projection into it of the 

 area occupied by the nuchal scute, which is 1 1 mm. wide. The thickness of the bone at the 

 articulation with the first peripheral is 21 mm.; at the articulation with the first neural, 6 mm. 

 The nuchal of the specimen of T. scripta mentioned has a maximum thickness of only 10 mm. 

 a fact showing that T . euglypha had a shell much thicker and heavier than that of the living 

 species. The width of the border which articulated with the first neural is 23.5 mm. 



The scutal sulci are deeply imprest. The nuchal scute has a length of 20 mm. and a width 

 of 10 mm., its lateral borders being parallel. That part of the first vertebral scute which lies 

 on the nuchal bone is 38 mm. long. Measured anteriorly between the points where the lateral 

 sulci ot the vertebral join the costo-marginal scutes, the width of the first vertebral is 34 mm. 

 Measured posteriorly, where the lateral sulci pass on to the first costals, the width is 50 mm. 

 I he upper surface of this bone is strongly sculptured, resembling somewhat that of T. 

 scripta, but ridged and grooved more boldly. 



