228 

 EMPO, Cope. 



Tliis genus is represented l)j very numerous remains in the chalk of 

 Kansas, and a consideral)lc amount of material pertaining to it has come under 

 my observation. The best-preserved remains are vertebrae and the jaws ; all 

 other portions of the skeleton are so fragile as to be difficult of extraction 

 from the matrix, but a few specimens preserved by the care of Professor Mudge, 

 of Kansas, have thrown especial light on these little-known parts of the 

 structure. 



The premaxillary bones arc longer than in any other genus here described, 

 and terminate anteriorly in a compressed-conic ape^ of dense bone. Medially, 

 they have greater transverse thickness and a semicircular section ; while, dis- 

 tally, they are compressed, and extended vertically. There is an unsymmctrical 

 crest on the superior border, the only point of contact with the ethmoid. The 

 maxillary is continuous from this point, and is usually attached by the coossi- 

 iication of a squamosal suture. It is vertical and Hat, and probably of no 

 great extent. The extremity is broken off in the specimens. While the pre- 

 maxillary supports two scries of teeth, the maxillary presents but one. 



The dentaries support several series of teeth ; one of large ones on the 

 inner side, and several smaller on the outer. The small ones are double- 

 edged, and diminish in size to the external margin ; the imier ones are like 

 the large ones of the maxillary series, with a flattened cutting apex. A strik- 

 ing character observed in two species of the genus {E. nepcsoUcn and E. semi- 

 anceps) is the absence of any angular process of the mandible ; the narrow 

 angular bone being ti'uncate vertically from the transverse cotylus. 



There are other tooth-bearing bones, which I cannot positively locate. 

 Some of these are laminiform, and are covered on one edge, and for some dis- 

 tance on the adjacent sides, with a dense brush of small acute conic teeth. 

 Tnis bone is palatine or pterygoid. Another is a massive tongue-shaped bone 

 with one narrowed extremity, and the other expanded into a lamina in the same 

 plane. It supports a median series of teeth, mostly in two rows, whose 

 crowns are curved and sin)ply conic. This bone is sometimes nearly symmet- 

 rical, so as to resemble a vouier; but in others it is distinctly unsymmetrical. 

 It is probably a superior or inferior pliaryngeal. In one specimen, it lies 

 pressed down on the dmitary, with the leetli on the inferior side. Another 

 bone is rod-like, with triangular section, with a single row of small conic 

 teeth set on the edge, whose section gives an angle. 



