golden, and following this a copper-colored tint; and so on through all conceivable hues, until finally, the end having come, change is interrupted in its course, and two tints are left in possession of the body—one in the act of disappearing, the other about to spread itself over the surface. That portion exposed to sunlight changes more rapidly, while the under side is
Fig. 3.—The Sword-Fish (Xiphias gladius
less gorgeous. Here we see a peculiar property possessed by many animals widely separated
in the scale of life—that of changing color at will, either to suit the surrounding shade, as illustrated in the chameleon and dolphin, or to attract certain kinds of prey, as seen in many of the lower marine animals—which becomes so much a habit in the case under consideration that, even when death is at hand, the changes are all passed through involuntarily.
Stormy petrels, or Mother Carey's chickens, as they are more commonly called, follow the outbound vessel in large flocks, gathering about as soon as land is lost to view, and remaining until the shore is once more sighted, unless a violent storm drives them
