1897.] NEW YORK ACADEMY OF SCIENCES. 303 



ties these American Dipnoans possessed, their teeth are alike in 

 their flattened or slightly arched form and the rounded smooth 

 obtuse tubercles which formed rows on the crown surface. 



The unique specimen upon which the above description was 

 based was found in the Catskill formation by Mr. Daniel Fleish- 

 er, Principal of the High School at Troy, Bradford count}'. Pa. 

 But a single specimen of the genus was before known in this 

 formation, P. arcuatus,'Sewh., from Tioga county, Pa. That 

 species, however, is much smaller and is to be distinguished 

 from this by the ridges of the crown, which are radiatel}' curved, 

 while in this they are straight. 



Ctenodus [Sagenodus (Ed.)'] angustus, n. sp. 

 PI. XXIV., fig. 26. 



Right mandibular tooth one inch in length b}^ one-fourth of an 

 inch in width, not including the projecting points of the salient 

 ridges. Crown surface smooth and polished throughout ; radi- 

 ating ridges five in number, the posterior two very short, obtuse ; 

 anterior three long-pointed, acute ; surface plain or slightly 

 waved ; the anterior ridge widely divergent from the others and 

 having a direction nearly parallel with the axis of the head. 



The specimen on which the above description is based is from 

 the Catskill rocks near Troy, Bradford county, Penns\'lvania, 

 where it was associated with Ctenodus Jieisheri, a species from 

 which it differs as widel}' as any two members of the genus. 

 The striking features of this tooth are its narrow, elongated form 

 and the three divergent, produced and pointed ridges of the 

 anterior extremity. The crown surface of the whole tooth is 

 highly polished. The ridges are rounded over without distinct 

 tubercles, all giving it a peculiar smoothness. In this respect it 

 resembles Ctenodus Isevis from the Chemung, but the form is 

 widely different. Like the species which bears his name this 

 was collected by Mr. Daniel Fleisher, near Leroy, Bradford 

 county. Pa. 



Stenognathus, n. gen. 



PI. XXIY., figs. 27-28. 



Many years ago Mr. J. Terrell found in the Cleveland shale at 

 Sheffield, Ohio, a small and imperfect jaw which is figured in 

 U. S. Geol. Survey Monograph XYI., p. 151, PI. VII., figs. 3 

 and 3 a and described under the name Dinichthys corrugatus. 

 Since the publication of that volume I have received from Mr. 

 Terrell another and much more complete jaw which shows that 



