y succeeded in capturing many
of its light-winged contemporaries, which it would have vainly pursued
in open sea, but may have been enabled also to present to its enemies,
when assailed in turn, only its armed portions, and to protect its
unarmed parts in its burrow. It is further worthy of notice, that many
of the Pimelodi are furnished with spines, not, like those
ichthyodorulites which occur so frequently in the older Secondary and
Palaeozoic divisions, unfinished in appearance at their lower extremity,
as if, like the spines of the ancient Acanthodi, or those of the recent
dog-fish (_Spinax acanthias_), they had been simply embedded in the
flesh, but bearing, like the wings of the Pterichthys, an articulated
aspect. Those of the _Pimelodus rita_ and _Pimelodus gagata_ are of
singular beauty; and when the creatures have no further use for them,
and the mud of the Ganges has been consolidated into shale or baked into
flagstone around them, they will make very exquisite fossils. A correct
drawing of the plates and spines of some of the members of the Pimelodi
family, with a portion of the internal skeletons, arranged in their
proper places, but divested of those more destructible parts to which
they are attached, would serve admirably to show what strange forms fish
not greatly removed from the ordinary type may assume in the fossil
state, and might throw some light on the extraordinary appearance
assumed, as ichthyolites, by the old family of the Cephalaspians.

The geological department of the Elgin Museum is not yet very complete.
The private collections of the locality, by forestalling, greatly
restrict the supply from the rich deposits in the neighborhood, and have
an unquestioned right to do so. The Museum contains, however, several
interesting organisms. I saw, among the others, a specimen of
Diplopterus, that showed the form and position of the fins of this
rather rare ichthyolite much better than any of the Morayshire specimens
portrayed by Agassiz in his great work; and beside it, one of the two
specimens of _Pterichthys oblongus_ which he figures, and on which he
establishes the species. The other individual,--a Cromarty
specimen,--graces my little collection. The gloomy day passed pleasantly
in deciphering, with so accomplished a geologist as Mr. Duff, these
curious hieroglyphics of the old world, that tell such wonderful
stories, and in comparing _viva voce_, as we were wont to do long years
before in leng