26 Short notices of American Fossil Fishes. 



Found at Westfield, Middlefield, and Durham, Ct. ; Sunder- 

 land, Mass. ; and Boonton, N. J. 



4. Palaeonisms Agassisii : W. C. R. — Large Palaeoniscus. 

 To this, which is the largest of the American species yet discov- 

 ered, I propose to affix the name of this distinguished naturalist. 

 Its length, in the specimens hitherto obtained, varies from seven 

 and a half, to ten inches, and its width from three to four inches. 

 The fins, with their armatures and insertions^ are also of more 

 remarkable thickness than in the species already noticed. The 

 large scales or plates which belong to the anterior portion of the 

 dorsal line, are commonly found doubled together at their lateral 

 edges, by the incumbent pressure, whicn gives them the appear- 

 ance of short spines, or flattened rays ; and hence these are some- 

 times mistaken for an anterior comb-hke dorsal. 



The same appearance is found, not unfrequently, in some of 

 the smaller species above noticed, and in two of the figures which 

 were published by Prof. Hitchcock, these narrowed and erected 

 scales are made to appear as a fringe-like dorsal fin. Prof. Agas- 

 siz has been led to place one of the figures thus drawn, in his ge- 

 nus Eurynotus, under the name of E. tenuiceps. The speci- 

 men thus figured, was probably a P. latus, or perhaps belonged 

 to another undescribed species. 



5. Palaeoniscus ovatus : W. C. R. — Wide, or round-shaped 

 Palaeoniscus. This species is shorter than P. Agassisii, and ex- 

 ceeds all the known American species in the comparative width 

 or roundness of its form ; and is also remarkable for the large 

 size of its scales. It is of rare occurrence, and owing probably 

 to its great thickness, is seldom obtained in a perfect form. This 

 fossil also exhibits the spine-like erections of the dorsal scales 

 which have been noticed above. 



Found at Westfield and Middlefield, Ct. ; Sunderland, Mass. ; 

 and Boonton, N, J. 



Genus II. Catopterus, of J. H. Redfield.* 



This genus is characterized by the backward position of the 

 dorsal fin, which is nearest the caudal extremity and opposite to 

 the anal fin. It is also distinguished by the articulated and 

 delicate form of the rays which compose the several fins. The 

 anterior margins of the latter are fringed with numerous small ray- 



* Described in the Annals of tlie New York Lyceum of Nat. Hist. Vol. iv. 



