On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 465 
-3 of an inch in thickness at a distance of one-third the length of the tooth from 
the posterior margin and diminishes to °2 in front. Crown ; either convex or con- 
cave in each, presenting the appearance of having been considerably worn by 
attrition towards the anterior extremity. The surface of the convex teeth are raised 
in the centre and along each lateral margin with a slight lateral depression within 
the margin ; the concave teeth are hollowed throughout with raised lateral margins. 
Surface covered with a thick coating of enamel anteriorly, where much used and 
worn the enamel is thin or quite removed; closely covered with minute punctures. 
Anterior border circular, ganoine or enamel slightly projecting beyond the bony 
structure of the base, and forming with the latter an acute angle. Laterally straight 
or slightly convex, retreating towards the base. Posterior border concave with the 
base projecting beyond the crown to give support to the anterior portion of the 
succeeding tooth. Latero-posterior angles produced in a line with the lateral margin 
so as to form hornshaped extensions, widely separated by the posterior surface 
of the tooth. Base; surface roughly striated longitudinally, slightly concave, 
thickest in the centre and thinning off towards each side. 
This species may be distinguished by the horn-like prolongations from the 
latero-posterior angles, one-third or more of the length of the central axis of the 
crown, they are continued in a straight line with the sides of the tooth, and are 
widely separated from each other posteriorly. 
A second palate was considered by Prof. Agassiz to constitute a separate species, 
to which the name of ©, lunulutus was given. The discovery of specimens with 
Copodus cornutus, and C. lunulatus attached in such a position as to prove that 
they are only one species, renders the latter species superfluous, and it is therefore 
included in the former. : 
The second and smaller teeth are more or less crescentic in outline, anterior wargin 
circular, laterally much produced, posterior margin slightly curved or straight ; the 
length of the tooth is ‘35 of an inch along the median line, the breadth is °75 of an 
inch. ‘Transverse section, basal outline circular; greatest thickness in centre, °25 
of an inch, tapering laterally to -12 of an inch. Crown, convex, oval in centre, 
depressed towards lateral extensions, which are again raised. Surface covered with 
enamel, profusely punctate, the punctures descending through the enamel to the 
‘bony structure of the base. Anterior border, slightly circular, produced at each 
side to form in conjunction with the more strongly curved posterior margin, 
aliform lateral processes. The latter vary in size and form in different specimens, 
in some obtusely rounded, in others acuminate. From the anterior and posterior 
margins the base recedes, and is narrower than the crown, laterally the base 
extends beyond the prolongations of the coronal surface. 
The convexity of the anterior surface corresponds with the concave surface of 
the posterior margin of the larger tooth, as shewn in the figure (Pl. LVIII, 
figs. 2,5), Both these surfaces exhibit considerable modification in form in different 
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