REPORT ON FOSSIL FISHES. 23 
34 inches in length, but the extremities both of the head and of the upper lobe 
of the caudal fin being deficient, the total cannot have been less than 4 
inches. The other (fig. 5), which wants the greater part of the head as well 
as of the caudal fin, represents a fish of slightly smaller dimensions, whose 
original length was probably 34 inches. 
The shape is fusiform, moderately deep between the head and dorsal fin, 
thence tapering gracefully towards the tail. Some remains of the cranial roof 
bones in the parietal region show a closely granulated external surface, while 
the facial bones and those of the shoulder girdle are ornamented with wavy 
sub-parallel ridges. The scales are somewhat small, and, as usual, diminish in 
size and increase in obliquity towards the tail. On the flank scales (fig. 7) the 
ornament consists in the first place of very delicate closely placed grooves 
or furrows, often interrupted and intercalated, their direction in the upper 
part of the area being more or less oblique from above downwards and 
backwards, while in the lower they become parallel with the inferior margin. 
Towards the posterior margin a number of coarser foldings or elevations of the 
surface make their appearance, and presently end in about half a dozen rather 
strongly marked marginal denticulations. It may be mentioned that the 
minute striation is much less obvious on the smaller than on the larger of the 
two specimens. Posteriorly (fig. 8), as the scales become smaller, the ridging and 
striation become less prominent, and reduced to a few longitudinal grooves and 
punctures, which finally disappear near the commencement of the caudal fin, 
while at the same time the denticulations of the posterior margin become also 
fewer in number, and likewise ultimately disappear. The variations in the 
form of the scales on different parts of the body are in accordance with 
what is found in Elonichthys striolatus, Robisoni, &c. 
A considerable portion of the pectoral fin, the rays and their joints being 
however slightly dislocated, is preserved in the Jarger specimen, and affords 
sufficiently clear evidence that the principal rays of this fin were articulated up 
to their origins, the joints being rather longer than broad. A small ventral! is 
shown in the other specimen. The dorsal fin is placed nearly opposite the 
interval between the ventrals and the anal; it is not of very large size, 
and is short-based, acuminate, high in front, and concavely excavated 
posteriorly; the anal, situated between the ventrals and the caudal, is 
similar in size and shape. Both of these fins have their rays divided by 
transverse articulations, for the most part rather distant, and their ganoid 
joints are marked by one or two longitudinal ridges and furrows, sometimes 
also a tendency to more minute striation is observable. Dichotomisation 
of the rays occurs towards their extremities. The caudal is deeply cleft ; 
the lower lobe of moderate size; its rays, nearly quite smooth externally, 
are divided by distant articulations, which become, however, closer in the 
VOL. XXX. PART I. E 
