3.—The myths, traditions, and historical allusions from which their reality may be inferred require to be classified and annotated, and full weight given to the evidence which has accumulated of the presence of man upon the earth during ages long prior to the historic period, and which may have been ages of slowly progressive civilization, or perhaps cycles of alternate light and darkness, of knowledge and barbarism.
4.—Lastly, some inquiry may be made into the geographical conditions obtaining at the time of their possible existence.
It is immaterial which of these investigations is first entered upon, and it will, in fact, be more convenient to defer a portion of them until we arrive at the sections of this volume treating specifically of the different objects to which it is devoted, and to confine our attention for the present to those subjects which, from their nature, are common and in a sense prefatory to the whole subject.
I shall therefore commence with a short examination of some of the most remarkable reptilian forms which are known to have existed, and for that purpose, and to show their general relations, annex the accompanying tables, compiled from the anatomy of vertebrated animals by Professor Huxley:—
REPTILES CLASSIFIED BY HUXLEY.
The most bird-like of reptiles, the Pterosauria, appear to have possessed true powers of flight; they were provided with wings formed by an expansion of the integument, and supported by an enormous elongation of the ulnar finger of the anterior limb. The generic differences are based upon the comparative lengths of the tail, and upon the dentition. In Pterodactylus (see Fig. 2, [p. 18]), the tail is very short, and the jaws strong, pointed, and toothed to their anterior extremities. In Rhamphorynchus (see Fig. 8, [p. 18]), the tail is very long and the teeth are not continuous to the extremities of the jaws, which are produced into toothless beaks. The majority of the species are small, and they are generally considered to have been inoffensive creatures, having much the habits and insectivorous mode of living of bats. One British species, however, from the white chalk of Maidstone, measures more than sixteen feet across the outstretched wings; and other forms recently discovered by Professor Marsh in the Upper Cretaceous deposits of Kansas, attain the gigantic proportions of nearly twenty-five feet for the same measurements; and although these were devoid of teeth (thus approaching the class Aves still more closely), they could hardly fail, from their magnitude and powers of flight, to have been formidable, and must, with their weird aspects, and long outstretched necks and pointed heads, have been at least sufficiently alarming.
We need go no farther than these in search of creatures which would realise the popular notion of the winged dragon.
The harmless little flying lizards, belonging to the genus Draco, abounding in the East Indian archipelago, which have many of their posterior ribs prolonged into an expansion of the integument, unconnected with the limbs, and have a limited and parachute-like flight, need only the element of size, to render them also sufficiently to be dreaded, and capable of rivalling the Pterodactyls in suggesting the general idea of the same monster.
It is, however, when we pass to some of the other groups, that we find ourselves in the presence of forms so vast and terrible, as to more than realise the most exaggerated impression of reptilian power and ferocity which the florid imagination of man can conceive.