T. P. Barkas — On Ctenodus from the Coal-shale. 315 



work on the Flora of the Coal-period were obtained from collieries 

 in Northumberland and the adjoining county, Durham. It is only 

 within the last few years that close attention has been directed to 

 the investigation of the fauna of the Northumberland coal-fields. 

 The first systematic investigator of the fauna of the Carboniferous 

 period in this locality was Mr. Thomas Atthey, late of Cramling- 

 ton, now of Gosforth ; and within the last few years Messrs. Kirby, 

 Sim, Taylor, and Craggs have each secured good collections of the 

 Carboniferous fossils. 



Among the most numerous animal-remains discovered in the 

 Northumberland Coal-measures are those of various species of fishes 

 of the genus Ctenodus, of which as yet little is positively known, 

 further than that their oral armature was of a very peculiar descrip- 

 tion, and that their opercular plates and head-bones to a great extent 

 resemble those of Dipterus, as described by Hugh Miller.^ As the 

 species to which I am about to refer have been pre"\dously described 

 in the "Annals of Natural History" by Messrs. Hancock and 

 Atthey, but have not been figured, I desire to direct the attention of 

 the readers of the GsoLoaiCAii Magazine to figures of the largest 

 and most rare of the species obtained in our Northern coal-fields. 



In the articles just referred to there are seven species described, 

 six of which are new and one, Ctenodus cristatus, which is at present 

 in the Leeds Museum, was described and figured by Prof. Agassiz in 

 his "Poissons Fossiles," vol. iii. p. 137, pi. 19, fig. 16. Prof. 

 Agassiz figures four additional species in his "Monogram des 

 Poissons Fossiles du Vieux Gres-rouge," none of which correspond 

 with those referred to, which have by Messrs. Hancock and Atthey 

 been named Ctenodus tuherctdatus, C. corrugatus, C. ohliquus, G. ele- 

 gans, C. imbricatus, and C. elUpticus. 



Ctenodus cristatus is very rare in our coal-shale ; I have only suc- 

 ceeded in obtaining one specimen, but that fortunately has associated 

 with it a perfect sphenoid bone, a beautiful opercular plate, and 

 several of the head bones of the fish. At the edge of the slab con- 

 taining the specimen there are impressions of three tubercles, which 

 have been made by the tubercular prominences of another tooth, but 

 unfortunately the specimen which left the impressions has not been 

 obtained. The tooth now in my possession is two inches long, 1^ 

 inch broad, has twelve ridges strongly marked with sharp-pointed 

 denticles, and bears a considerable resemblance to the specimen in 

 Agassiz " Poissons Fossiles." The opercular plate is thick and strong, 

 and is rather deeply marked with vermicular reticulating lines, 

 somewhat resembling those which cover the maxillary bones of 

 Bhizodopsis, and which underlie the polished covering of the scales 

 and bones of Megalichthys ; it is If inch long, and If inch broad. 

 I have in my possession a large, nearly circular, opercular j)late, 

 which is supposed to belong to one of the Ctenodi ; it is 6^ inches in its 

 longer diameter and 6 inches in its narrower, and is about f of an 

 inch thick at its thickest part. To what species this large operculum 

 belongs I do not know; but assuming that it bears the same pro- 

 1 " Footprints of the Creator," p. 58, new issue. 



