45 

 EMPO, Cope- 

 Proceed. Amer. Philosophical Soc, 1872, 347 ; GimoUcMhys, Cope, loc. 

 cit., 348, (attributed to Leidy, but uot his genus). 



A large number of additional specimens have been examined since 

 the description above cited was published ; as several of these embrace 

 crania with the bones in i^lace, and greater or less portions of the bodies, 

 many important additions to the definition can be made. 



The anterior end of the maxillary is subconic and generally compressed, 

 as originally described under U. semianceps, and free from well-marked 

 sutural surface. The distal part of the bone has a greater vertical extent, 

 and exhibits points of attachment for bones or ligaments. This rela- 

 tion, the reverse of what might be supposed without violating analogy, 

 I have proved on two crania where they are in place. I have only seen 

 the premaxillary in one species, the E. semianceps. It resembles that of 

 Enchodus in its solid, massive character, and the presence of a prominent 

 tooth at the anterior extremity. It bears two teeth near the middle of 

 its length, a character which may be specific only. At the anterior ex- 

 tremity of the maxillary, there is a short series of large teeth, which con- 

 tinues gradually or abruptly into a series of much smaller teeth along 

 the inner or posterior border of the alveolar face. This terminates in one 

 or two abruptly larger teeth near the distal end of the bone. The outer 

 alveolar border is occupied by a row of teeth of large size, similar to 

 those at the proximal end^, which commences opposite the most distal ot 

 the latter. Their size is reduced opposite to the two large distal ones, 

 and is recovered again in the single row on the narrowed distal portion 

 of the maxillary. The teeth are compressed at the tip, and generally 

 bear one or more cutting edges. 



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 inner ones are 

 like the large ones of the maxillary series, with a flattened cutting apex. 



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 distance on the adjacent sides with a dense brush of small acute 

 conic teeth. This 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 simply conic. This bone is 

 sometimes nearly symmetrical, so as to resemble a vomer; but in others it 

 is distinctly unsymmetrical, and hence probably a lateral element. In 

 one specimen it lies pressed down on the dentary with the teeth on the 

 inferior side. Another bone is rod-like, with triaiigular section, with a 

 single row of small conic teeth set on the edge, whose section gives an 

 angle. This, doubtless, belongs to the branchihyal system, to which, -per- 

 haps, the piece first described may be attached. The latter I call the 

 pharyngeal bone until fully identified. 



The vertebrae are not grooved as in USaurodontidw, but sculptured with 

 raised lines only on the greater part of the column. Posteriorly deep 

 lateral grooves appear. The ribs are well developed, and the abdominal 

 cavity not elongate. Ventral fins are not in the abdominal position in 

 the best identified specimens of E. sulcata. Ko strong fin-rays can be 

 certainly referred to the genus. The body was covered with very large 

 scales on the side and on the middle line of the back; some of the latter 

 having the character of shields. They have the surface, in some spe- 



