210 FOSSIL TURTLES OF NORTH AMERICA. 
Cope arranged this genus among his Propleuride. The cordate form of the carapace 
in the state collection at Adlanea: deeply excavated in front and pointed behind, appears to 
indicate close relations with the Cheionide and to this family the species is here provisionally 
assigned. 
Peritresius ornatus (Leidy). 
Chelone ornatus, Leipy, Proc. Acad. Nat. Sci. Phila. 1856, p. 303; Smithson. Contrib. Knowl., xiv, 
1865, pp. 105, 119, plate xvi, fig. ro. 
Perttresius ornatus, Copr, Cook’s Geol. New Jersey, 1868 (1869), p. 735; Amer. Naturalist, 11, 1869, 
p. 88; Ext. Batrach., Reptilia, Aves N. A., 1870, p. 150; Vert. Cret. Form. West, 1875, p. 260; 
Amer. Naturalist, ut, 878, p. 129.—Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 
This is yet an imperfectly known species. It was based by Leidy on conjoined portions 
of two lateral peripherals, which had been found in Cretaceous greensand in Burlington 
County, New Jersey. This greensand probably, but not certainly, belonged to the upper 
bed. The bones are probably now in the collection of the Philadelphia Academy, but they 
have not been seen by the present writer. They were described by Leidy as measuring an 
inch and a half in breadth and as being we edge- shaped in section. The outer border was 
acute; the inner border grooved, and eight lines, about 17 mm., high. Both the upper and the 
lower surfaces were coarsely, but beautifully, tuberculated, and the tubercles showed a tendency 
toward a radiate arrangement. Some of the tubercles at the ends of the peripherals are 
lengthened out into ridges. Cope states that there were no indications of dermal sulci on the 
bones. He mentions also a costal which he thought belonged at least to the genus. 
Under the species Taphrosphys nodosus the present writer has suggested that it may be 
identical with the species here described. 
In the collection of the Geological Survey of Georgia is the greater portion of the carapace 
of what appears to have been a large sea-turtle. This specimen was at one time in the hands 
of Prof. E. D. Cope and was by him identified as Peritresius ornatus Leidy (Amer. Naturalist 
1, 1878, p. 129). Considering the facts that Leidy’s type consisted of portions of two 
evidently hinder peripherals and that all the hinder peripherals of the Georgia specimen are 
wanting we can not be sure that the identification is correct. For the present it may be allowed 
to ane Undoubtedly it was on this specimen that Cope based his definition of the genus 
Peritresius. It is not known why Cope concluded that there were g pairs of costals. 
The specimen here described was found by Mr. Loughridge, of the Georgia Geological 
Survey, then under the direction of Dr. George Little, in fhe Ripley formation! of the Upper 
Cretaceous, on Bonnahachee Creek, Stewart County, Georgia. It presents most of the carapace, 
but unfortunately the left side is yet concealed by a mass of matrix. This has prevented an 
accurate study of the specimen and the production of a figure. The length of the portion pres- 
ent is 675 mm. ina straight line, 735 mm. over the curve. The original | length of the carapace 
must have been about goo mm. In form the carapace is cordate, like that of are -tta. Anteriorly 
there is an excavation in the border 200 mm. wide and about 30 mm. deep. The free border is 
obtuse and the bone is about 16 mm. thick. The costals are about 8 mm. thick. The anterior 
peripherals are suturally joined to the first costals. Behind this they are missing; but it is 
evident that some of them were connected with the costals only by gomphosis of the ios 
The most conspicuous feature of the carapace is the great dorsal keel. This begins on the 
nuchal bone and continues to the rear of the carapace. Te) is thick and obtuse on the anterior 
half of the carapace. Here the sloping sides of the keel are very steep, the summit is obtuse, 
and the height is about 36 mm. Posteriorly the summit is more acute. 
On account of the great number of fractures it is difhcult to follow the sutures. Where 
observed these are coarse and zigzag. A few of the sulci are traceable. The third vertebral 
scute has a width of about 125 mm. The sulci forming its lateral boundaries are nearly parallel 
with the axis of the animal. 
The whole upper surface of the carapace is coarsely pitted and ridged, much like that of 
some species of Trionychide. 5 or 6 ridges are usually to be counted in a line 25 mm. long. 
The anterior border of a second specimen is in the same collection. Found with it is the 
greater portion of the united dentary bones. The triturating surfaces are flat. The length 
of the symphysis is 53 mm. 
