426 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
Only posterior tooth known; itis more elongate, narrower, flatter, and has a more 
twisted conformation than the teeth of Streblodus oblongus. It averages 1°6 inches 
in length and °55 inch in breadth across the posterior ridge, its widest part. 
Crown, with three ridges and intermediate hollows. The first or anterior ridge 
defines the anterior margin ; it is straight, acute, narrow, and at right angles to the 
long axis of the tooth. The second or median ridge, extends at an angle of 45° to 
the first. one, it is ‘1 inch wide, semicircular, and rises from an almost uniformly 
flat or slightly concave depression extending on each side the ridge with a total 
diameter of half the length of the tooth. Posterior ridge, large, wide, expanding 
obliquely from the anterior margin of the tooth backwards. Surface enamelled, 
uniformly punctate; in several cases the surface is worn flat or hollowed by 
attrition. Front of tooth inrolled downwards, the ridges extending therefrom 
radially and increasing in size, especially the third one, backwards ; posterior angle 
acutely elliptical ; adpressed. Base conforms generally to the crown, thick, strong, 
slightly concave. Towards the posterior ridge the tooth is “45 inch thick. 
This species exhibits several well marked differences from S. oblongus. Its 
general appearance is more attenuated, and in proportion to the length it is much 
narrower. The surface is less convex ; the posterior ridge is narrower, and extends 
more obliquely across the tooth. The second ridge, which in S. oblongus is toler- 
ably broad with a narrow sulcus on each side, in S. colez is a narrow band rising 
from a wide depression of the surface extending several diameters of the ridge on 
each side. 
Formation and locality : Mountain Limestone, Armagh. 
Ex coll. Far) of Enniskillen, 
Streblodus egertoni, Agass. MSS. 
QPL IWNNE. ines % Sy) 
Streblodus egertoni—L. Agassiz, 1859. “MS. Enniskillen Coll.,” 
i i Morris & Roberts, 1862. ‘Quart. Journ. Geol. Soc.,” Vol. XVIII, ». 101 
*3 ‘3 Enniskillen, 1869. “Cat. Foss. Fishes, Types,” p. 8. 
5 es J. J. Bigsby, 1878. “Thes. Dev.-Carb.,” p. 365. 
Posterior teeth, small, oblong, sub-conical, deeply incurved in front; antero- 
posterior section of anterior portion circular. Length °6 inch, breadth “3 inch. 
Crown, anterior ridge, at right angles to longitudinal axis, forms a prominent 
acutely angular anterior margin, surface slopes gradually in the opposite direction 
forming a wide concave depression occupying half the breadth of the tooth ; there 
is not a median ridge. Posterior ridge rises abruptly from the depressed concave 
portion, extending obliquely from the convoluted anterior margin, gaining in breadth 
posteriorly and ending in an obtusely rounded posterior margin. Surface 
coarsely punctate. 
This beautiful little species, dedicated to Sir Philip Egerton by his friend Prof. 
Agassiz, whilst possessing the generic characters of Streblodus, is distinguished from 
