of a gentleman long resident
in India, to which Mr. Duff called my attention, as illustrative, in
some of the specimens, of the more characteristic ichthyolites of the
Old Red Sandstone. One numerous family, the Pimelodi, abundantly
represented in the Gangetic region, in not only the rivers, but also the
ponds, tanks, and estuaries of the district, is certainly worthy the
careful study of the geologist. It approaches nearer, in some of its
more strongly-marked genera, to the Coccosteus of the Lower Old Red,
than any other tribe of existing fishes which I have yet seen. The body
of the Pimelodus, from the anterior dorsal downwards, is as naked as
that of the eel; whereas the head, and in several of the species the
back, is armed with strong plates of naked bone, curiously fretted, as
in many of the ichthyolites of the Lower, and more especially of the
Upper Old Red Sandstone, into ridges of confluent tubercles, that
radiate from the centre to the edges of the plates. The dorsal plate,
too, when detached, as in many of the species, from the plates of the
head, bears upon its inner side a strong central ridge, that deepens as
it descends, till it abruptly terminates a little short of the
termination of the plate, exactly as in the dorsal plate of Coccosteus,
which sunk its central ridge deep into the back of the animal. The point
of resemblance to be mainly noticed, however, is the contrast furnished
by the powerful armature of the head and back, with the unprotected
nakedness of the posterior portions of the creature;--a point specially
noticeable in the Coccosteus, and apparent also, though in a lesser
degree, in some of the other genera of the Old Red, such as the
Pterichthyes and Asterolepides. From the snout of the Coccosteus down to
the posterior termination of the dorsal plate, the creature was cased in
strong armor, the plates of which remain as freshly preserved in the
ancient rocks of the country as those of the Pimelodi of the Ganges on
the shelves of the Elgin Museum; but from the pointed termination of the
plate immediately over the dorsal fin, to the tail, comprising more
than one half the entire length of the animal, all seems to have been
exposed, without the protection of even a scale, and there survives in
the better specimens only the internal skeleton of the fish and the
ray-bones of the fins. It was armed, like a French dragoon, with a
strong helmet and a short cuirass; and so we find its remains in the