74 Dr. J. S. Newberry on American Fossil Fishes. 



Prof. Wm. Hopkins, " On a remarkable fossil," <fee. — Proc. American As- 

 sociation, 1854, p. 28Y. 



Dr. J. S. Newberry : Fossil Fishes of the CliflF Limestone of Ohio.- 

 Annals of Science, vol. i, 1853.— Proc, Amer. Assoc, 1853, p. 166; 

 Bulletin of the National Institute, 1857, p. 119. 



" peracutus, N 



" sulcatusy N. 



Onychodus Hopkinsi, N. 

 " sigmoides, N, 



" multiseriatus 



The three genera proposed in this paper, namely, Agassichihy. 

 a large ccelacanth ganoid; Onychodus, represented by a grony c^" 

 placoid teeth, and Machaer acanthus, based on some remarkable 

 unsymmetrical double-edged spines, as they are characteristic oi 

 the formations in which they are found, and of considerable 

 zoological interest, seem to require a few words of descriptive 

 comment. 



Of these, the first, I am now satisfied includes the ichthyic om- 

 nium described by Doctors Owen and Norwood under the gt:"' 

 eric name of Macropetalichihys. The specimen described b}' 

 these gentlemen was found in the Cliff limestone at ^ladisori, 

 Indiana. When it came into their hands, it was nmch brokou. 

 As a consequence the description based upon it was very uU' 

 perfect, and in some respects erroneous, and, as will be seen, 

 sure to mislead any one who might discover other representa- 

 tives of the genus to which it belonged. Dr. Owen described 

 his fish as "being entirely destitute of a tubercled dermal surtaoo ; 

 as without distinct eye-orbits; provided with two spin- 

 pendages, or horns, and having the scutcheons covoi' 

 angular, irregular, rhomboidal, enamelled, but minute - 

 all of wlaich is entirely at variance with the characteristic- 

 large number of crania which I have examined, dcri\'eu '• 

 the same formation, and which, judging from a plaster ca^; , 

 the original which I have seen, are generically identical wi'^- 

 that described by Dr. Owen. 



