﻿306 R. Etkeridge, Jun. — Contributions to Palceontology. 



iv. furtheb conteibutions to british carboniferous 



Paleontology. 



By Egbert Etheridge, Junior, F.G.S., etc. 



{Continued from the June Number, p. 251.) 



(PLATE XIII.) 



Class Pisces. Genus Fissodus, St. JoIid and Wortlien, 1875. 



Fissodus, St. J. and W., 1875. Illinois Geol. Eeport, vol. vi. p. 413. 

 Fissodus Pattoni, sp. nov. Plate XIII. Figs. 2 and 3. 



Sp. Chars. — Tooth bidenticulated with a re-entering angle between 

 the denticles ; sides sloping down to the lateral angles : anterior 

 profile convex ; posterior profile concave. The most prominent 

 portion of the anterior surface is at the centre of the inferior margin 

 of the crown, where it becomes bowed-out, whence the surface 

 gradually recedes to the cutting edge of the crown on the one hand, 

 and more rapidly towards the root on the other. Superior and 

 inferior margins of the crown symmetrical ; no coronal ridges on 

 the anterior ; anterior surface of the crown smooth, but, where worn, 

 Avith a coai'sely-fibrous appearance. On the posterior face of the 

 tooth the enamel-like layer only just caps the two denticles, and 

 is traceable as a thin line into the re-entering angle between them, 

 and are bounded inferiorly by a thickened ridge ; the convex portion 

 of the anterior face is here represented by a concavity. Eoot long, 

 attenuated, or oblong. 



Obs. — I believe it is now becoming generally acknowledged that 

 many of the so-called species amongst the Carboniferous " palatal " 

 teeth are mere variations of other well-marked forms. Notwith- 

 standing this, I think we are justified in assigning names, provisionally 

 at any rate, to teeth which appear to be different from those already 

 known, until such can be shown to be individuals of a series repre- 

 sented by some previously well-known form. Acting under this 

 belief, I have given the above name to the elegant little tooth now 

 figured, in honour of Mr. A. Patton, to whom I have been frequently 

 indebted for the loan of fossils from his cabinet. My friend, Mr. W. 

 Davies (of the British Museum), was kind enough to examine and 

 compare one of the specimens with the extensive collection of teeth 

 in the National Collection, and informs me that it is unknown to him. 



I believe I am correct in referring them to the above recently 

 established genus, although one of the characters ascribed to Fissodus, 

 viz. the ear-like lateral angles, is certainly not represented here, 

 the latter being definitely rounded. Of the two described species, 

 Fissodus hijidus, St. J. and W., and F. tricuspidatus, St. J. and W., 

 our tooth very closely resembles the former ; but there is the partial 

 generic difference noticed above, and there is an entire absence of 

 imbricating ridges at the base of the crown, in addition to other 

 minor points. 



Loc. and Horizon. — Obtained by Mr. A. Patton from shale im- 

 mediately above the Calderwood Cement Stone, Lower Carboniferous 

 Limestone Group, at the Kirktonholra Cement Mine, East Kilbride, 

 Lanarkshire ; also roof of the Splint Coal, Edge Coal Series, Dean 



