The faces of these vertebræ were nearly flat, and not hollow like those of the Icthyosaurus, which would better enable the animal to exist on land, and it appears to have moved about in the same manner as seals do. From some very ingenious observations on certain parts of its anatomy, (which if I were to endeavour to explain to you, you would not understand, unless you possessed a great deal of anatomical knowledge,) naturalists have supposed that it used to change the colour of its skin like the chameleon. Its paddles were almost exactly like those of the turtle, and its body was something of the same shape, but not quite so wide. From its long neck, which, although it was strengthened by the solid joints and peculiar shapes of the bones, was not very strong, and its small head and jaws, the Plesiosaurus could not have been near a match for its neighbour, the Icthyosaurus, in combat, even when the individuals were of the same size; neither would its form adapt it for cutting through the water so quickly. It must, therefore, no doubt, have often fallen a prey to that voracious monster. Perhaps, however, it often played him a trick when he was pursuing it by running on shore out of his reach; or it might mostly have kept out of his way in very shallow water amongst the rushes and reeds, where it could every now and then dart its long neck like a swan, down at the little fish that came near it; or else suddenly reaching aloft into the air, it may have seized upon some unlucky insect, or Pterodactyle, (a sort of bat of which I shall presently speak) and then laid down as quiet under the rushes as if nothing had happened, waiting for its next mouthful. THE PTERODACTYLE. That odd-looking creature which is flying in the air over the heads of the Plesiosauri, has been called the Pterodactyle, which signifies _wing-fingered_. There were several varieties, of different sizes and figures, from that of a snipe to that of a raven. The most remarkable of them was indeed a curious creature, and so you will say if you look at the picture of his skeleton. [Illustration] He was more like a bat in his general shape and habits, than anything else we know of, but was very different in a great many respects.