29 



TEIONYX, Geoffr. 



Trionyx foveatus, Leidy. Proceed. Academy, Philadelphia, 1856, p. 

 73. Transac. Amer. Philosoph. Society, 1860, 148, tab. 

 Bad lands of Judith Eiver, Montana. 



TRIONYX VAGANS, Sp. nov. 



Trionyx ffoveatuv, Leidy. Proceed. Acad. Nat. Sci., Philadelphia, 1856, 



p. 312. 



Eepresented by a number of fragments of costal bones, and perhaps 

 of sternals also. ' The former are rather light or thin for their width, 

 and are marked with a honeycomb-pattern of sculpture, in which the 

 ridges are thin and much narrower than the intervening pits. They 

 incline to longitudinal confluence at and near the lateral sutures. Sev- 

 eral areas are not uufrequently confluent in a transverse direction near 

 the middle of the bone. 



Width of costal bone 0370 



Thickness of costal bone 0045 



Four and five, areee in 010 m. 



This species differs from the T. foveatus, Leidy, in the much narrower 

 interareolar ridges and larger arese and in their longitudinal confluence 

 at the margins, characters exhibited by numerous specimens. 



Lignite cretaceous of Colorado ; near the mouth of the Big Horn 

 Eiver, Montana ; Long Lake, Nebraska ; found at the last two localities 

 by Dr. Hay den. 



PLASTOMENUS, Cope. 



Annual Report U. S. Geol. Survey, 1872, p. 617. 

 PLASTOMENUS(I) PUNCTULATUS, Sp. noV. 



Established on a costal bone found in association with the preced- 

 ing species, and referred to the genus Plastomenus provisionally, and 

 with a probability that it will be found not to pertain to it when fally 

 known. That genus has so far only been found in the Eocene formation. 

 The bone is rather thin and sufficiently curved to indicate a convex car- 

 apace of moderate thickness. The surface is marked with closely packed 

 shallow pits without material variation of form on the proximal half of 

 the bone. The result is an obsolete sculpture quite similar to that seen 

 in some species of the genus to which it is at present referred. 



Width of costal bone 0230 



Thickness of costal bone 0033 



Number of pits in .010 m six. 



Lignite Cretaceous of Colorado. Also several fragments from Long 

 Lake, Nebraska, from Dr. Hayden. 



Plastomenus(!) insignis, Sp. nov. 



Eepresented by a portion of the right hyposternal bone of a tortoise 

 about the size of the last species, and from the same locahty. The speci- 

 men resembles in its sculpture such species as the Flastomenus triony- 

 choideSj and in structural character the species of Anostira, but it is 



