1()7 



rowed. Tlie ridge is so proiniiicnt, as to create a wider face or surface behind 

 the basis of the great ala tlian exists between the latter and the edge of the 

 auricular meatus. This basis is quite convex inward, and embraces a relatively 

 smaller space than in any other Pythonomorph. A section of the bone at the 

 meatus is subtrilatcral, with a notch behind. The distal articular surface is 

 prolonged below the origin of the great ala, and receives the keeled termina- 

 tion of the internal ridge. 



Measurements. 



u. 



Total IciiKtli of tlio, qiiiulrato 0. l.')3 



Length from tbo superior to tlio inferior orijiin of the great ala 0. OdO 



Length of the external angle from the basis of the ala 0. 05'i 



The two usual ridges pass inward and downward from the meatal knob. 



The above quadrates are flattened from within outward by pressure. 



A portion of the palatine l)one, supporting the teeth, displays the char- 

 acters of the type, viz, the inner face vertical and deeper than the outer, 

 and forming a strong parapet of bone on the superior or toothless aspect ; the 

 outer face a little expanded laterally ; the bases of the teeth exposed. It is 

 proper to add that the locality ascribed to the type-specimen, "near Fort 

 Hays, Kansas," which was originally given rae on inquiry, is erroneous. 



LlODON DYSPELOR, Cope 



The type-specimen, which first indicated the characters of this species, 

 was obtained from the yellow beds of the Niobrara epoch of the Jornada del 

 Muerto, near Fort McRae, New Mexico. The greater part of the remains 

 have been described by Professor Leidy/ and a few only of the vertebrae 

 came under my inspection. A second specimen, more complete in all respects, 

 was discovered by my party during my expedition from Fort Wallace, Kansas, 

 in 1871, which is fully described and figurcil in the present work. 



In the first specimen, the centra of the dorsals are much depressed, qiiilc 

 as in L. perlatus, Cope, and Mosasaurus hrumbyi, Gibbes. Their articular 

 faces are of transverse lenticular form, the superior arch being a little more 

 convex than the inferior, and obtusely emarginate for the floor of llie neural 

 canal. The superior outline is thus bilobed ; the lobes rounded. The trans- 

 verse curvature of the articular ball is quite regular, and not, as in Arosasaurun 

 7}ia.vimu.s, more steeply inclined at the external or lateral angles. A rather 



' Report of the United States Geological Survey by Haydeu, vol. I, p. 'i7l. 



