306 R. Etheridge, Jun. — Contributions to Palceontology. 
IV. — Further Contributions to British Carboniferoüs 
PaLJEONTOLOGY. 
By Robert Etheridge, Junior, F.G.S., etc. 
( Continued from the June Number, p. 251.) 
(PLATE XIII.) 
Class Pisces. Genus Fissodus, St. John and Worthen, 1875. 
Fissodus, St. J. and W., 1875. Illinois Geol. Report, vol. vi. p. 413. 
Fissodus Pattoni, sp. nov. Plate XIII. Figs. 2 and 3. 
Sp. Chars. — Tooth bidenticulated witli 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, 
with 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. Root long, 
attenuated, or oblong. 
Obs. — I believe it is now becoming generally acknowledged that 
many of the so-called species amongst the Carboniferoüs “ 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 
lcnown, until such can be shown to be individuals of a series repre- 
sented by some previously w r ell-known form. Acting linder this 
belief, I have given the above name to the elegant little tooth now 
figured, in honourof Mr. A. Patton, to whom I have been frequently 
indebted for the loan of fossils from bis cabinet. My friend, Mr. W. 
Davies (of the British Museum), was kind enough to examiue 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, altkough 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 bifidus, 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 Carboniferoüs 
Limestone Group, at the Kirktonkolra Cement Mine, East Kilbride, 
Lanarkshire ; also roof of the Splint Coal, Edge Coal Series, Dean 
