A NEW SPECIES OF SAGENODUS FEOM THE KANSAS 

 COAL MEASURES. 



COBTEIBUTION TEOM PALEONTOLOQIOAL LABOKATORY No. 50. 



BY S. W. WILLISTON. 



With Plates xxviii, xxxv, xxxvi, xxxvii. 

 S(f{/(ii(K7us Owen. "Body depressed, covered with large thin scales, al- 

 most quadrate in shape, but having the angles well rounded; both scales and 

 external bones destitute of a ganoine layer. A large, median occipital plate pos- 

 teriorly, with a smaller median plate immediately adjoining the front margin of 

 this element ; dental plates above and below triangular, irregularly ovate or el- 

 liptical in form, with a few strong, outwardly directed, more or less tuberculated 

 or crenulated ridges; vomerine teeth resembling a single ridge of a dental plate; 

 dorsal and anal fins continuous with the caudal." Woodward, Cat. Foss. Fishes 

 Brit. Museum, ii, 256. 



Twenty-one species of North American paleozoic dipnoans have 

 been referred to this genus, based exclusively upon dental plates or 

 scales ; the generic determination of the latter species must be more 

 or less uncertain. In the University museum there is a considerable 

 collection of bones belonging to a species of this genus, which I can- 

 not identify with any of the described forms. They were obtained by 

 Dr. J. W. Beede at Robinson, in Brown county, this state. The hori- 

 zon is rather above the middle of the Coal Measures, and the speci- 

 mens were intimately associated with others of Somphospongia 

 Beede, described in the last number of this journal. 



Before discussing the species, I will give a list of the described 

 species of the genus from North America, together with a brief diag- 

 nosis of the more important characters of each, so far as they can be 

 gathered from the existing descriptions. Most of the species have 

 never been figured, thus rendering the elucidation of the characters 

 more diflBcult. The reference of the species, when not otherwise in- 

 dicated, is upon the authority of Woodward (1. c.) 



Sagenodus paucicrif^totns Cope, Proc. Amer. Phil. Soc, xvii, 1878, 53 

 {Ceratodus). Permian, eastern Illinois. 



Dental plate 17 mm. in length from base of second ridge ; four 

 ridges present ; surface minutely and elegantly corrugated. 



[175]-K.U.Qr.— A viii 4-Oct. '99. 



