t to have been an
essentially aquatic animal, moving after the fashion of the Sea-Turtle.
Its so-called wings resemble in structure the front paddles of the
Sea-Turtles far more than the wings of a Bird; differing from them,
indeed, only by the extraordinary length of the inner toe, while the
outer ones are comparatively much shorter. But, notwithstanding this
difference, the hand of the Pterodactylus is constructed like that of an
aquatic swimming marine Reptile; and I believe, that, if we represent it
with its long neck stretched upon the water, its large head furnished
with powerful, well-armed jaws, ready to dive after the innumerable
smaller animals living in the same ocean, we shall have a more natural
picture of its habits than if we consider it as a flying animal, which
it is generally supposed to have been. It has not the powerful
breast-bone, with the large projecting keel along the middle line, such
as exists in all the flying animals. Its breast-bone, on the contrary,
is thin and flat, like that of the present Sea-Turtle; and if it moved
through the water by the help of its long flappers, as the Sea-Turtle
does now, it could well dispense with that powerful construction of the
breast-bone so essential to all animals which fly through the air.
Again, the powerful teeth, long and conical, placed at considerable
intervals in the jaw, constitute a feature common to all predaceous
aquatic animals, and would seem to have been utterly useless in a flying
animal at that time, since there were no aerial beings of any size to
prey upon. The Dragon-Flies found in the same deposits with the
Pterodactylus were certainly not a game requiring so powerful a battery
of attack.

The Fishes of the Jurassic sea were exceedingly numerous, but were all
of the Ganoid and Selachian tribes. It would weary the reader, were I to
introduce here any detailed description of them, but they were as
numerous and varied as those living in our present waters. There was the
Hybodus, with the marked furrows on the spines and the strong hooks
along their margin,--the huge Chimera, with its long whip, its curved
bone over the back, and its parrot-like bill,--the Lepidotus, with its
large square scales, its large head, its numerous rows of teeth, one
within another, forming a powerful grinding apparatus,--the Microdon,
with its round, flat body, its jaw paved with small grinding teeth,--the
swift Aspidorhynchus, with its long, slender body and mas