PERMIAN VERTEBRATES 703 



Sagenodus vinslovii Cope. Plate I, Figs. 6a, 6b. 



Ceratodus vinslovii Cope, 1875, Proc. Phil. Acad. Nat. Sc, p. 



410. 

 Ceratodus vinslovii Cope, 1877, Proc. Am. Rhil. Soc, p. 54. 

 Ptyonodus vinslovii Cope, 1877, Proc. Am. Phil. Soc, p. 192. 



(Pal. Bull., No. 26.) 

 Sagenodus vinslovii Woodward, 1 89 1 , Cat. Foss. Fishes Brit. 



Mus., Pt. II, p. 262. 

 Sagenodus vifislovii Williston, 1899, Kans., Univ. Quart., 



Series A, p. 176. 



"The crown of the tooth is in general outline an oval, wider at one end 

 than the other, the inner border gently convex and entire. The outer border 

 is marked by six shallow notches which are separated by as many sharp, 

 compressed projections. The emarginations and denticles are the termini of 

 corresponding grooves and ridges, which radiate from a smooth space along 

 the inner margin of the crown. From this plane the grooves gradually 

 deepen to the margin ; the separating ridges are acute and without irregular- 

 ity or serration. The base or root of the tooth is quite wide. Externally it 

 extends beyond the border of the crown at the notches, and has projections 

 corresponding to the denticles, from which it is separated by a horizontal 

 notch. On the inner side the base extends like a shelf beyond the posterior 

 half of the crown, and is produced backwards beyond its posterior border. 

 The inferior plane is concave in transverse section; the crown is plane in all 

 directions." 



MEASUREMENTS. 



" Length of crown preserved ----- .o2i m 



Width crown ------- .013 



Length of root preserved .... - .022 



Depth of root internally - - - - - .005 



Depth of root externally ----- .003 



"This Ceratodzis {Ptyonodits) resembles the species described by Agassiz 

 under the name of C. parvus and C. serratus from the English Trias, but 

 differs from them in the shortness of the tooth-like processes. In none of 

 the species do I find such a development of the basis on the inner side." 



[No. 6507.] 



