76 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



"The edge of the posterior articular face is excavated opposite to the 

 chevron facets. The latter are large, are separated by a flat surface, and are 

 bordered externally by a raised edge from the polished dense layer of the 

 lateral face. 



"Measurements. 

 "Diameter of centrum (intercentrum) : m 



Vertical 0.021 



Transverse 019 



Longitudinal on 



Width of neural canal 006 



Width of neurapophysis 004" 



In the second paper cited, Cope described a dorsal intercentrum of this 

 species as a distinct species, C. discophorous; he corrected this in the third 

 paper. The description is as follows: 



"The centrum (intercentrum) is diskiform,'^with very short antero- 

 posterior diameter, which is, however, greater at one part of the surface 

 than at the opposite point. The foramen chordce dorsalis occupies about 

 one-fifth of the transverse diameter, which is subequal in all directions. 

 The articular faces of the centrum are slightly concave. The margin of that 

 of one side is beveled for the superior two-thirds of the circumference, the 

 bevel running out below by turning into the articular face. The latero- 

 inferior border of the latter turns out into an obtuse angle at this point. 

 The superior part of the bevel runs into the lateral face of the centrum. The 

 attachment of the neural arch is obscure or wanting in the specimen, and 

 the same is true of any facet for chevron bones. 



"Measurements. 

 "Diameter of articular face: M 



Vertical 0.025 



Transverse 025 



Length of centrum below .009 



Length of centrum above 007 



a 



'Another vertebra of nearly the same character, and one-half smaller 

 in size, presents a greater difference between the long diameters of the upper 

 and lower sides. The superior diameter is only one-half the inferior, and the 

 foramen chordce dorsalis much nearer the superior than the inferior margin. 

 Its diameter is one-fourth the vertical and one-third the transverse diameter." 



In the third paper Cope gave an extended account of the species, but 

 the specimens on which it was founded were subsequently, 1884 (38), made 

 the type of a new species, C. crassidiscus. 



Revised description: See C. crassidiscus . 



Cricotus crassidiscus Cope. 



Proc. Am. Phil. Soc, vol. xxii, 1884, p. 28; Proc. Am. Phil. Soc, vol. xvii, 1878, 

 p. 522 (C heteroclitus partim); Am. Nat., vol. xviii, 1884, p. 39 (C heteroclitus 

 partim). 



Type: Two imperfect skeletons, Nos. 4550, 4550^ Am. Mus. Nat. Hist. 

 Cope Coll. From Texas. 

 Original description: 



"I. Dorsal intercentra much narrowed or pinched above. Hypantrum 



unknown C. heteroclitus 



IL Dorsal intercentra equally robust above as below, or more so. 



Hypantrum unknown C. crassidiscus 



Hypantrum with acute lateral processes C. hypantricus" 



