On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 423 
M‘Coy. An examination of the specimen in the Woodwardian Museum at Cam- 
bridge has shown this to be the case, and also that the figures of the specimen given 
in the “ British Palaozoic Fossils” are not exactly correct. The illustrations given 
above are from two specimens of C. contortus, Ag. ‘There are others equally well 
prepared of Streblodus oblongus, Ag., which prove quite as conclusively that the 
teeth of Streblodus were developed in the same manner as those of Cochliodus. 
The “Geological Magazine” (Vol. IV., p. 59) contains the description of a man- 
dible of a Cochliodont by Prof. Owen. It is from the Mountain Limestone of Bristol. 
« Apparently the whole of the dentary part of the right ramus and the anterior halt 
of that of the left ramus are here shown (op. cit. pl. 111., fig. 2). ‘he posterior end 
of the right dentary is of little breadth and depth, but it gains in both, and chiefly 
in the latter dimensions, as it approaches the symphysis, and there rapidly acquires 
great breadth and thickness. ‘The lower border is thick and rounded, the outer 
side moderately convex ; the inner side, somewhat wavy, being concave lengthwise 
at its middle part. The hind part of the symphysis extends back like a shelf, from 
below the dentigerous surface of that part of the mandible.” This specimen is re- 
ferred to the genus Tomodus of Agassiz, but a comparison of the specimen with the 
type specimens of that genus in the Enniskillen collection is at once conclusive that 
the one described by Prof. Owen is not a Tomodus but in all probability a crushed 
specimen of Cochliodus contortus, Agass., to which it certainly bears a close 
resemblance. 
Formation and locality : Mountain Limestone, Bristol. 
Ex coll. Enniskillen collection ; Bristol and Woodwardian Museum. 
Genus Streblodus, Agass, MSS., 1858. 
Syn. Cochliodus—L. Agassiz, 1838. “ Poiss. Foss.,” Vol. III., p. 174. 
Teeth, medium or small size, three teeth to each ramus of the jaw. Anterior 
tooth, small, convex, sub-triangular in outline; median tooth, larger, sub- 
quadrate, highly convex, margins connecting it with anterior and_ posterior 
teeth, straight, inclined at a slight angle to the longitudinal axis of the tooth. 
Posterior tooth, large, convoluted anteriorly and extending and expanding in 
diameter backwards or inwards. Crown of posterior tooth characterized by a series 
of two or three ridges with intermediate hollows extending radially from the anterior 
margin. Third or posterior ridge covers about one-half the surface of the crown. 
Coronal surface enamelled, punctate. 
TRANS. ROY. DUB. SOC., N.S., VOL. I. 3X 
