This however is not at all more wonderful than the eye, which in the old-fashioned animal I have been describing, was much larger than that of the crocodile, and not unfrequently bigger than a man's head. From the very great quantity of light which such a large surface would receive, the creature's power of seeing must have been very great. And besides this advantage, it had the same faculty as is possessed by the golden eagle, the turtle, the tortoise, and the lizard, of pressing the eye forward to render it more convex. In man and most animals, the eye is placed in a fixed cavity of thin bone, something like an egg-cup, but in the Icthyosaurus, the cavity was formed by several bones not quite touching each other; (as you may see in the last cut, and in figure 2, you have two of the bones by themselves, taken out of the socket of the eye;) and there were muscles to draw these bones closer together; so that by making the cup less deep, the eye was thrust forward and made to swell out in the middle. This is illustrated in the ball _b_, which is pressed outwards, by drawing the plates of bone _cc_, together at _o_, close than those which have the ball _a_ between them. [Illustration] You must have seen that the more convex magnifying glasses are, the more they magnify, and the nearer you must hold them to the object you are looking at. By this contrivance, the eye of the Icthyosaurus could be made at pleasure into a microscope, so as to see with wonderful quickness things which were quite close to it, by pushing it forward and rendering it more convex; or it could be made into a telescope like the eyes of some persons who are long-sighted, for seeing what is at a greater distance, by drawing it back. In all these particulars you may see how the skill of man leads him to adopt the same plans to produce the same ends in the works of art, as God has adopted before him in the works of nature, without his being conscious of copying them; and this should remind you that man was created in the image of his Maker. If man had never made a carriage-spring, or a diagonal bracing, he would not have understood the structure of the jaw of the Icthyosaurus; and if he had never invented the telescope, he would not have been able to explain the construction of the eye. You have now seen the points in which the Icthyo-saurus chiefly resembled a crocodile or lizard; from which the latter half of its name is derived, _saurus_, _a lizard_. I must now tell you something of those parts in which it is like a fish, from which it takes the other part of its name, _icthy_, for _icthus_, a fish.