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HE geological age of reptiles was marked by various curious, seemingly only partly perfected forms, which appear to have passed away without leaving any permanent descent. To it belong the relics of those flying reptiles, the Rhamphorhynchus and the Pterodactyls. The type of the pterodactylean wing was not at all like that of the wings of birds, which were yet to come, and were beginning to appear when the reptilian era approached its close. The apparatus for flying was not formed by any essential modification of the limbs, but rather, like that of the bats, was constituted by a broad fold of the skin, attached to and sustained by the digits of the fore-limb. The last or outer digit, greatly elongated, formed a rigid side bordering and sustaining the parachute, which was further attached along the full length of the arm, and in the Rhamphorhynchus was continued to the tail. These animals also had a long tail ending in a membrane, sustained by rigid ribs, that served as a kind of rudder.

There were giants and dwarfs among the pterosaurians. Of the former were the Pteranodus, of the Kansas Cretaceous; and of the latter, little Jurassic pterodactyls, which were not larger than a lark.

The hieratic traditions of dragons appear at first sight to have been inspired* by the singular forms of these monsters; and it would be easy enough to suppose that the simple-minded figure-makers of the middle ages were acquainted with the pterosaurians, and patterned after them in sculpturing the dragons and griffins which they set up at church entrances. But they did not. Man's imagination is always capable of associating different forms into individuals, and even of inventing new forms. That the dragons of art were such inventions is proved by the awkward attachments which the artists affixed to their strange conceptions. Some of their creatures, if living, would have had a hard task to fly with the wings they gave them; and others would have been greatly embarrassed to make use of all the appendages with which a hand more lavish than wise had endowed them.

Movement by flying, the realization of which is still only a dream for man, has had a charm for the mystics of all ages. All religions concur in the common fancy of putting wings on the shoulders of their gods, genii, cherubim, angels, and seraphim. There were necessary for the transportation of such forms, for company and service, and to do battle for them, animals having forms likewise supernatural and agile; whence hippogriffs,