8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 18, 



I have a specimen presented to me by the Baron de Ponsort from 

 the coal-measures of Liege, which differs from the genus PalcBoniscus 

 in the small size and pointed form of the scales, and in the greater 

 thickness of the body immediately in advance of the caudal fin. The 

 form of this fish is also in other respects very distinct from PalcEoniscus, 

 The specimen is too imperfect to describe, but perhaps this notice 

 may produce more satisfactory materials for the determination of the 

 generic and specific characters. 



Genus Ischypterus, Egerton. 



Mr. W. C. Redfield, in alluding to the description of Palceoniscus 

 fultus given by Agassiz *, says, " the stout character of the fins and 

 their insertions (which suggested to Agassiz the specific name) is also 

 found to pertain in a greater or less degree to all the known American 

 species of the genus, and would perhaps warrant their separation from 

 the PalcBoniscif." Fully concurring in this view, I suggested to 

 Sir Charles Lyell J the propriety of eliminating these fishes from the 

 Agassizian Palceonisci and grouping them together under the generic 

 name of Ischypterus, a term expressive of the common character no- 

 ticed b)^ Mr. Redfield. Of the five species described by Mr. Redfield, 

 Agassiz cowsid^QY^ I. fultus midi I. macrojpterus to be identical §. I 

 am not cognizant of any species of this genus found at Antrim, as 

 stated by Sir C. Lyell||. 



Genus Catopterus, J. H. Redf. 



This genus has been well characterized by Mr. J. H. Redfield^, with 

 the exception of an error regarding the form of the tail, which has 

 since been corrected by Mr. W. C. Redfield in the memoir quoted 

 above**. In addition to the original species, named C. graciliSy 

 Mr. W. C. Redfield has described three species ; of these, C. macrurus 

 must be canceled as being the type of a new homocerque genus — 

 JDictyopyge^-^y Egerton. 



Catopterus Redfieldi, Egerton. 



On looking over a large collection of fossil fishes from Durham, 

 Connecticut, forwarded to me by Sir C. Lyell for that purpose (and 

 to whom I communicated the results), I found evidence of another 

 species of Catopterus, to which I gave the above specific name in com- 

 pliment to the original discoverer of the genus. 



Genus Gyrolepis, Ag. 



The scattered and fragmentary condition in which the remains of 

 this genus have always been found, has proved hitherto an insur- 



* Poiss. Foss. vol. ii. p. 43. 



t Short notices of American Fossil Fishes, by W. C. Redfield, read before the 

 Yale Nat. Hist. Soc. April 28, 1841. 



+ Journal of Geol. Soc. vol. iii. p. 277. § Ibid. vol. iii. p. 277. 



Ij Ibid. vol. iii. p. 278. 



^ Annals of New York Lyceum of Nat. Hist. vol. iv. p. 39. 

 ** American Journal of Science, vol. xli. p. 26. 

 ft Journal of Gegl. Soc. vol. iii. p. 275. 



