On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 503 
I take the liberty of appending the nomen triviale, Colet, to this beautiful species 
in appreciative acknowledgement of the indebtedness of all students of Ichthyology 
to the bearer of that name, the Earl of Enniskillen. 
This species bears some resemblance to the tooth figured as Dactylodus princeps, 
N. and W. (“ Paleon. of Illinois,” Vol. IL, p. 45, pl. iii., fig. 6). The latter is deeper 
and narrower, whilst the fangs are very long, on the anterior face the roots occupies 
seven-tenths of the entire height of the tooth. 
From all the British species P. colei is quite distinct and separate ; from P. 
- radicans itis distinguished by its greater height, broad crown, narrower space 
occupied by the roots as compared with the breadth of the crown, and the fewer, 
more robust, and rotund rootlets. The only other species to which it approaches is 
P. sinuosus whose characteristics can scarcely be mistaken. 
Locality : Carboniferous Limestone of Armagh. 
Ex coil, Ear] of Enniskillen, 
Polyrhizodus elongatus, Davis. 
(Pl. LX., figs. 16, 16a, 160.) 
Teeth, length 2°75 inches, height 1:2 inch. The general outline of this species 
is much broader in proportion to its height than P. radicans, but not so contracted 
as P. attenuatus. The coronal surface is barely °5 of an inch in greatest breadth, 
which is maintained along two-thirds of its length ; at each end it tapers rapidly to 
a point, much depressed. The surface is slightly convex, covered with ganoine, 
and where not worn, slightly punctate. The anterior median ridge is separated 
from the crown by a considerable depression forming a long groove: the ridge is 
composed of a strong single fold of ganoine, more deeply punctate than the crown, 
and extending in a nearly straight line across the tooth, near the lateral extremities 
it is bent downwards diagonally forming the end of the tooth and continued alone 
the posterior surface. The posterior surface of the crown occupies a much larger 
area than the anterior, its greatest vertical depth is ‘9 of an inch. Its upper 
boundary, with that of the anterior coronal surface, forms an acutely pointed crest. 
The surface deeply concave and rough as though for the attachment of muscles, 
The posterior median ridge prominent with three or four wavy, imbricating folds, 
extending in an almost straight line across the spine ; it is separated from the root 
by a deep groove. The root, separated from the anterior ridge by a sloping bony 
surface equal in breadth to that of the crown, is divided into fourteen to sixteen 
radicles or rootlets, circular, flattened, lobe-like; the flat sides lying parallel, separated 
by half their own diameter. The radicles are -4 of an inch in length and the same 
width from back to front, they occupy a more forward position with respect to the 
crown of the tooth than any other species from the Armagh district. 
- In another example the anterior coronal surface from the median ridge backwards 
is much depressed, and forms a concave instead of a convex surface, towards the 
TRANS. ROY. DUB, SOC., N.S., VOL. I. 4H 
