REPORT ON FOSSIL FISHES. 59 
The form of the body is therefore very deep ; the back is rounded (though 
with a slight angle at the origin of the dorsal fin), and enormously gibbous ; 
the ventral line is nearly straight as far as the origin of the anal fin, where it is 
obtusely angulated, and slopes upwards to the commencement of the tail 
pedicle. 
So far as the osteology of the head is decipherable, it conforms to the type 
characteristic of this genus ; the cranial bones are ornamented externally with 
delicate, close, wavy subparallel striz, occasionally passing into minute tuber- 
cles. Very distinct imprints of teeth are seen upon the mandible, clearly show- 
ing that these were minute, cylindro-conical, slightly enlarged towards the 
apex, then bluntly pointed. 
The shoulder girdle presents nothing specially worthy of remark. 
The body scales are of moderate size, becoming indeed rather small towards 
the dorsal and ventral margins and the caudal extremity, where, as usual, they 
are also more equilateral. A typical scale from the flank, just behind the head, 
is high and narrow, with well-marked articular spine, and strong internal mar- 
ginal rib or keel. The covered area is narrow; the exposed one rhombic, with 
very acute anterior-inferior and posterior-superior angles, and is ornamented 
with fine vertical striz, about twelve in the space of 4 inch, perfectly parallel, 
and hardly ever bifurcating or intercalated. On the scales further back, and 
towards the margins, especially the ventral one, these strize often become more 
irregular and wavy, while bifurcation and intercalation very commonly occur. 
By careful working out on the counterpart immediately behind the lower 
part of the clavicle, I succeeded in uncovering a considerable part of the pec- 
toral fin, but not in displaying its perfect contour. Its length is 1-4; inch, being 
greater than the distance between its origin and that of the ventral. 
A little in front of the origin of the anal fin a well-developed ventral is 
exhibited ; it is one inch in length, short-based, and acuminate in form, and is 
composed of numerous rays, which are tolerably closely articulated, and dicho- 
tomise towards their terminations, 
The dorsal fin is remarkable for the large size which it attains both from the 
length of its base and of its rays. It commences at the culminating point of 
the back, slightly in front of the origin of the ventrals, and forms a deep fringe 
extending to the tail pedicle. Its most anterior rays are very short, but they 
rapidly elongate till a length of 14 inch is attained at the apex, behind which 
the contour of the fin again falls away somewhat, and passes back tolerably 
parallel with the base. The length of the rays in the posterior part is ? inch, 
but from the broken up appearance of their extremities, both here and towards 
the apex, it is evident that the full depth of the fin is not exhibited in the 
specimen, a conclusion amply borne out by a fine fragment of a smaller specimen 
to which I shall presently refer. The very numerous dorsal fin rays are ganoid 
