64 Bulletin American Museum of Natural History. [Vol. XIX, 



in length, but the tips are broken off. From the anterior 

 they grow shorter and slenderer to the last. Probably 

 nearly the whole, if not the whole, of the fin is present. The 

 ravs divide longitudinally into slender portions but show no 

 signs of segmentation. The nine vertebrae have a length of 

 185 mm., and the fin has about the same length along its base. 



Pachyrhizodus leptopsis Cope. 



Pachyrhizodus leptopsis Cope (E. D.), Bull. U. S. Geol. and Geog. 



Surv. I, No. 2, 1874, p. 42; Vert. Cret. Form. West, 1875, pp. 



225, 276, pi. li, figs. 8-8c. — Stewart (A.), Univ. Geol. Surv. 



Kansas, VI, 1900, p. 354, pi. Ixx, fig. i. — Woodward (A. S.), 



Cat. Foss. Fishes, IV, 1901, p. 45. — Hay (O. P.), Bibliog. and 



Cat. Foss Vert. N. A. 1902, p. 388. 

 Pachyrhizodus lepitopsis LooMis (F. B.), Palaeontogr. XLVI, 1900, p. 



264. 



This species was based on a fragment of a right dentary 

 which presents the symphyseal surface. The specimen bears 

 the Museum's number 1756. The species is characterized by 

 the large size of the bases of the teeth and the narrow symphy- 

 seal articulation. The bases on which the teeth rest are large, 

 fully as wide as long, and the empty spaces from which the 

 teeth have fallen are about circular. In P. caninus the teeth 

 are crowded, so that the tooth bases, measured across the 

 jaw, are wider than long, and the empty spaces are of greater 

 extent across the jaw than parallel with it. 



Oricardinus sheareri Cope. 



Pachyrhizodus sheareri Cope (E. D.), Proc. Amer. Philos. Soc. XII, 

 1872, p. 347; U. S. Geol. Surv. Wyoming, etc. 1872, p. 348; 

 Bull. U. S. Geol. and Geog. Surv. I, No. 2, 1874, p. 43; Vert. 

 Cret. Form. West, 1875, pp. 225, 276. — Woodward (A. S.), Cat. 

 Foss. Fishes, IV, 1901, p. 45. 



Oricardinus sheareri Cope (E. D.), Proc. Amer. Philos. Soc. XVII, 

 1877, pp. 177, 178. — Hay (O. p.), Bibliog. and Cat. Foss. Vert. 

 N. A. 1902, p. 388. 



Pachyrhizodus sheari Loomis (F. B.), Pal^ontogr. XLVI, 1900, p. 264. 



The type of this species is supposed to be a portion of the 

 left maxilla. A figure and section of the specimen is here- 



