Cope.] 196 [Nov. 2, 
COMPSEMYS PLICATULUS, sp. nov. 
Although tortoises have been discovered in older formations in Europe, 
the present species is the earliest yet obtained in North America. Its 
characters appear to coincide in important respects with those of the Lig- 
nitic formation which I have referred to Compsemys Leidy. This name I 
have proposed to retain for tortoises with marginal bones completely 
united with solid plastron, and the usual dermal scuta, and which differ from 
Hmys in their Trionyx-like sculpture. 
The C. pitcatulus is represented by portions of both carapace and plas- 
tron of several individuals. While the distal extremities of the costal bones 
display the suture for the marginals, they also possess an inferior true costal 
prolongation, as in Trionyx. The proximal part is not preserved in any 
marginal bone, but the adjacent portions were united by fine suture. The 
proximal extremity of the costals exhibit the usual two directions, the 
shorter being posterior, and relating to the anterior part of the succeeding 
vertebral bone. The sternal sutures are fine; that between the hyo- and 
hyposternal bone is transverse ; while that between the latter and the post- 
abdominal is oblique, and at the margin quite squamosal. At that point 
the hyosternal underlaps the post-abdominal for a considerable distance, 
and the suture of the inferior side of the plastron, after bending forwards, 
is abruptly recurved, running along the edge of the posterior lobe. 
The scutal sutures are not wide nor deeply impressed, but the abdomino- 
femoral, and the femoro-anal are distinct. The median, longitudinal, sternal, 
and the costo-marginal sutures are irregular and serpentine. The sculp- 
ture is rather fine, and consists of rather closely placed tubercles and ridges. 
The borders of the elements of both carapace and plastron are marked 
with ridges at right angles to the sutures, which are not short. The mid- 
dle parts of the costal bones are marked by short interrupted or inoscula- 
ting vermicular ridges closely placed. On the middle portions of the sternal 
bones the ridges are in places more broken, forming tubercles. 
The surface of the bridge is angularly oblique to that of the plastron. The 
buttresses are not produced inwards. The free marginal bones are rather 
thin, and are not recurved. 
Measurements. M. 
Length of avcostaldbpnes a. kincaid eee ee sete ai-ieiots) werk 
Width of the sametenin-e seme mee emerie ss conte ce eae 
Thickness ‘ AG LaT encase! shoe cee asters Beis Sens isis ct vor om as OU. 
ene thy or hiypostenmeal sp Omer -sepsterertetdetts tir tele erale re tote 066 
Width of the same at inguinal notch...... apononn oped» lke: 
Mhicknessvol the same nnmetrOntseeeremele ecient OU 
Found by Superintendent Lucas with the foregoing species. 
