400 PALEONTOLOGY OF OHIO. 



rinthic structure. A characteristic feature is seen in the presence of a 

 large elongate tooth in the upper jaw, in the position of a canine, which 

 much exceeds in length any of the others. The sculpture of the cranium 

 is little marked in the known species. In the type the lower jaw is 

 marked with inosculating grooves. Two species are known, which are 

 the largest of the Linton fauna. 



Leptopheactus obsoletus, Cope. 



Proceedings Acad Nat. Science, Philadelphia, 3873, p. 341. 



The teeth are rather distantly grooved for some distance above the 

 base. They are of different sizes; the smaller are compressed, and with 

 fore and aft cutting edges. 



The external surface of the dentary bone is marked with short oblique 

 grooves along its middle region ; above these are grooves which inoscu- 

 late, formiag a figure like an opsn net dragged in the long direction. 

 Excepting the grooves, the teeth are smooth. The smaller ones are close 

 together, and their crowns are curved backwards; the larger ones are at 

 more remote intervals; both have enlarged bases. Whether both forms 

 are in the same series I can not determine. There are from four to five 

 of the smaller in an inch. 



Depth of fragment of jaw (margin wanting), .075 m. ; length of smaller 

 teeth, .019; length of longer do., .023; width of vertex at middle scuta, 

 .176 ; width of paired median scuta, .056 ; width of single do., .036 ; length 

 of single do., .048. 



Some vertebrae were found at the same locality, but there is no evi- 

 dence as to the species to which they may have pertained. They are 

 short, concave on one end, and probably so on the other. The centrum 

 of one is .012 m. in diameter; neural arches injured. (PI. 39, fig. 3.) 



A third and larger specimen was found by Prof. Newberry during the 

 field season of 1874. It includes an oblique view of one side, and the 

 top of the cranium from the posterior part of the orbits to the end of the 

 muzzle, with the corresponding part of the alveolar region of the dentary 

 bone, with teeth. The bones of the skull appear to have been rather 

 light, and though the surface s irregular, the sculpture consists only of 

 shallow impressions of varying size and intervals. The orbits are also 

 badly defined, but appear to have been large, and separated by a narrow 

 frontal bone. The premaxillary bone is preserved, and shows clearly 

 the sutures that separate it from its fellow and from the maxillary. A 

 large foramen — perhaps the nostril — separates it from the maxillary, so 



