yellow colour of the buccal cavity which is thereby revealed, and the display of which supplies, in my opinion—as in the other cases I have brought forward—the true motive of the bird's conduct in this respect. Handsome—or, at any rate, outré—as the puffin's beak is, it is hardly, if at all, more striking to the eye than is this vivid gleam of one bright colour, revealed suddenly in a flash-light by this distension of the mandibles. It is like the sword gleaming out of the scabbard, whose brightness comes as a surprise, whereas the latter, however rich and ornate, is a permanent quantity, and so lacks the charm of novelty. The fact that the puffin's beak is a superlative ornament does not, in my opinion, render it unlikely that there should be another one lying within it. It is absurd in such a matter to say that this or that is enough, and in the puffin's case we are certainly debarred from doing so, since not only has the beak been decorated, but the parts adjacent to it, as well as the whole head, have also been, so as to join in the general effect. The eye is almost as salient a feature as the beak itself, and moreover, where the mandibles meet at their base, there is on either side a little orange button or rosette, formed by foldings of the naked skin, which must certainly rank as a sexual adornment in the eyes of all who believe in such a thing, and with which, apparently—as in the other cases—the inner coloration is continuous.
The puffin, therefore, makes the seventh species of sea-bird in which, as I believe from my own observa-
