On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 509 
inch, height of crown ‘15 to ‘2 inch. Crown: median ridge extends along central 
longitudinal axis, straight, uniform, without serrations or cones—anterior surface, 
shght convexity from apex to base ; laterally straight or convex ; posterior surface 
parallel with the anterior one, concave in both directions ; anterior and posterior 
ridges somewhat expanded, margins occasionally serrated. Lateral borders oblique 
and angular. Coronal surface enamelled, apex deeply and coarsely punctate. A 
number of concentric imbricating folds or plicee encircle the base of the crown, 
parallel with its margin. Base not well exposed, appears to be short, and deeply 
and doubly concave. 
An example in the Enniskillen collection, from the Mountain Limestone of 
Richmond, in Yorkshire, differs in some respects from the Armagh type. The 
tooth is broader in the central portion in proportion to its length, laterally it 
becomes attenuated, and ends in a more or less acute point. The surface is 
punctate, and wide and irregularly sinuous folds extend along the anterior surface, 
most strongly marked near the apex,-whilst near the base they are almost imper- 
ceptible. . On the posterior surface the plice or folds are arranged concentrically ; 
they are smaller and more numerous. Though this specimen differs in several 
respects from the type, and it is not improbable that it may belong to a separate 
species, yet it will perhaps be advisable to retain it with Chomatodus linearis, Ag., 
until more extended observation shall have demonstrated its real characteristics. 
Formation and Locality : Mountain Limestone. Armagh, Bristol, Richmond in Yorkshire, 
Kx coll. Earl of Enniskillen. 
Chomatodus acutus, Davis. 
(EES IXa tot 2a.) 
Chomatodus linearis, Ag., “‘ Poiss. Foss.,” p. 108, Tab. XIL., fig. 5-13. 
Tooth, not perfect, broken at one end, length preserved ‘7 inch, depth anteriorly 
*3 inch, posteriorly -2 inch, width equal to the posterior height. Crown, trans- 
versely acuminate ; apex, thin razor-shaped, with sharp cutting edge, straight ; 
anterior and posterior surfaces concave with slight vertical corrugations, slightly 
expanded to form the ridges:separating the crown from the base ; base not exposed. 
This species differs from C. linearis, Ag., in the acutely pointed knife-like apex of 
the crown, and in the constricted character of the anterior and posterior margins. 
Formation and locality : Carboniferous Limestone, Armagh. | 
He coll. Karl of Hnniskillen. 
Genus.—Glossodus, M‘Coy. 
Glossodus.—F. M‘Coy, 1848, Ann. and Mag. Nat. Hist., 2nd Ser., Vol. IT., p. 127. 
Teeth, tongue-shaped, oblong, quadrangular, much higher than wide ; 
crown elevated, shghtly recurved, narrowing from the base to a small, sub- 
truncate apex; surface porous, puncta generally seeming confluent towards the 
