THE PERMIAN FISHES OF NORTH AMERICA 165 



Sagenodus periprion (Cope). (Plate 27, figs, 5-5<i.) 



1878. Ctenodus periprion Cope, Proc. Amer. Philos. Soc, xvii, p. 527. 



1881. Ctenodus periprion Cope, Amer. Naturalist, xv, p. 162. 



1888. Ctenodus periprion Cope, Trans. Amer. Philos. Soc, xvi, p. 285. 



1891. Sagenodus periprion (Cope), Woodward, Cat. Fos. Fishes, Brit. Mus., 11, 



p. 261. 

 1899. Sagenodus periprion (Cope), Williston, Kans. Univer. Quart., Ser. A, viii, 



p. 176. 



Type: A left palatal plate, defective at anterior and posterior extremi- 

 ties. No. 7474 Am. Mus. Cope Collection. Texas. 



Original description: "This large species is indicated by a fine palatal 

 tooth of the left side. Its outline approaches that of a right-angled triangle, 

 but the hypothenuse is deeply incised by the interradial notches. The plate 

 is rather thin, and is moderately concave on the inferior face. The ridges 

 number seven, all of which are directed outwards and forwards. They are 

 separated by strong grooves, have a perfectly smooth and uniform crest, 

 and become more elevated at the distal extremities. The latter are steeply 

 decurved and serrate, both faces being invested with a polished enamel-like 

 layer. This substance is only visible in an edge view, and covers one-half 

 the depth of the margin, being excavated by the extremities of the radiating 

 grooves. The superior face is flat. 



"The absence of serration from the radiating ridges of this species is 

 a striking feature, allying it to the genus Ptyonodus, where the teeth are 

 wanting. 



"Measurements. m 



"Length of dental plate 0.037 



Width of dental plate 018 



Thickness at inner border 005 



Thickness at external border of penultimate crest 007" 



Sagenodus vinslovi (Cope). (Plate 27, figs. 7-8.) 



1875. Ceratodus vinslovi Cope, Proc. Acad. Nat. Sci. Phila., p. 410. 



1877. Ceratodus vinslovi Cope, Proc. Amer. Philos. Soc, xvii. 



1877. Ptyonodus vinslovi (Cope), Ibid., p. 192. 



1891. Sagenodus vinslmi (Cope), Woodward, Cat. Fos. Fishes, Brit. Mus., 11, p. 262, 



1899. Sagenodus vinslovi (Cope), Williston, Kans. Univer. Quart., Ser. A, viii, 



p. 176. 



1900. Sagenodus vinslovi (Cope), Case, Journ. Geol., viii, p. 703, pi. I, figs. 6a-6b. 



Type: A left palatal plate defective at anterior extremity. No. 6507 

 University of Chicago Gurley Collection. Vermilion County, Illinois. 



Referred specimen: A left palatal from Texas, also defective anteriorly. 

 No. 7233 Am. Mus. Cope Collection. 



Revised description: Dental plate relatively thin; coronal face traversed 

 by six ridges radiating from an inner smooth area, which occupies one-third 

 to one-half the width of the entire element; ridges smooth, without serrations, 

 rising gradually towards their distal extremities, which are cusp-like. De- 

 pressions between ridges wide and shallow. 



