374 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
the C. levis, M‘Coy, agrees with the much-worn, smooth specimens of C. marginatus 
given above. 
Formation and locality : Mountain Limestone, Armagh. 
Hz coll, Earl of Enniskillen. 
Cladodus elongatus, Davis. 
(Pl. XLIX., figs. 10, 11.) 
Teeth, large, very prominent median cone, variable number of lateral cones, 
those placed externally considerably the largest. Base large and expanded, sub- 
elliptical, more oy less rounded behind ; anterior margin straight with the exception 
of the median portion which is curved inwards, rounded at the extremities, 
moderately thick, diminishing in thickness backwards, lateral diameter of base 1:6 
inches, from front to back, °7 inch. Median cone 1°3 inches in height with 
sigmoidal curvature °3 of an inch wide at base, that width being maintained with 
very slight diminution one half the height, it then tapers gradually and terminates, 
in specimens not much worn, in an acutely pointed apex; transverse section, sub- 
triangular; anterior surface slightly convex, laterally produced so as to form a 
cutting edge; posterior surface deeply convex, with median angularity towards 
the apex; anterior and posterior surface uniformly striated. Lateral cr secondary 
denticles number five on each side. The two external ones are large, firmly 
implanted, accuminate, striated similarly to median one; they are 45 inches in 
length slightly and sigmoidally curved with points deflected outwards. Intermediate 
cones small, equidistant, 15 of an inch long. In addition to the more prominent 
denticles indicated, there are, in very well preserved specimens, others very minute 
and apparently interspersed without definite arrangement. 
This species is distinguished by its largely expanded, flat base, and the peculiarly 
long and graceful proportion of the median tooth. In general form it most nearly 
approaches Cladodus striatus, Ag., from Tynan in Ireland ; it differs from that species 
in the characters just indicated. This species also bears some resemblance to 
examples found in the lower Kinderhook fish-beds of Illinois, especially Cladodus 
alternatus, St. J. & W.,(“Geol.Sury. Ill.,” Vol. VI., p. 265, pl. 2, figs. 14-18. This may 
be distinguished, however, by the alternate secondary denticles being of unequal 
length, and its smaller size. C. grandis, N. & W.(“Geol. Surv. Ill.,” Vol. II., p. 29 
pl. L., fig. 15), similar in form, is separated by its compressed form of median cone and 
the irregular arrangement of the secondary ones. 
Formation and locality, Mountain Limestone, Richmond and Settle. 
Ex coll. Reed collection, York Museum. 
