78 CATALOG OF FOSSIL FISHES IN THE MUSEUM. 



Stenognathus insignis? 



E 1957 A small left antero-superognathal which from its size, 

 texture of the bone, and the fact that the tooth is rather 

 weak and might have fitoctioned against just such a beak 

 as that of the Stenognathus insignis mandible (fig. 24), 

 we deem it probable that the specimen belonged to that 

 species. The element is small: height, 25 mm., greatest 

 width, 12. The point of the tooth is slightly reflexed 

 upward and outward, and the articulating process is 

 broad, flat and narrowly elliptical in cross-section — ^not 

 subcircular as in Dinichthys. 



Conodont bed, (Genesee); Eighteen Mile Creek, near 

 North Evans, Erie County, N. Y.; collected by W. L. 

 Bryant. 



Selenosteus sp. 

 (Text-fig. 26) 



This genus is indicated by two imperfect mandibles and several 

 fragmentary armor plates from the Rhinestreet shale (Portage), at 

 Eighteen Mile Creek. So far as we are aware, this is the first record 

 of the occurrence of Selenosteus in New York state. 



In this genus the head and armor plates are very thin, the denti- 

 tion feeble, and the remains seem to have been tossed about a good 

 deal and to have become broken or abraded before fossilization. It is 

 one of the rarest of all American Arthrodires. 



The mandibles described below are very close to those of Selenos- 

 teus brevis (Claypole)^^ from the Ohio shale, but are of smaller size. 

 They are not completely enough preserved to allow of a detailed com- 

 parison with the mandibles of this species, so that we are not certain 

 whether they represent this or a distinct form. On the other hand, as 

 there are no body plates in our material that can positively be said to 

 belong with these mandibles, there is at present insufficient ground on 

 which to base the description of a new species. It seems probable that 

 when better known this fonn wiU turn out to be new. 



E 2393 A small left mandible, lacking the anterior, functional por- 

 tion (fig. 26, a). It is represented mostly as an impression 



5^ For synonymy of this form see Hussakof, L.: Upper Devonic Arthrodira from Ohio in the 

 British Museum (Nat. Hist.). Geol. Mag., [s], viii, 123-128, pi. viii, 1911. 



