pretty rose tapestry of the mouth-chamber must be plain to each or either, and the more so that they are vis-a-vis.
In all these four birds, therefore, we have a nuptial habit of distending the jaws, side by side with a brilliant or pleasing coloration of the region which, by such action, is exhibited. Moreover, in the case of one of them, more particularly—viz. the fulmar petrel—this distension may be unaccompanied with any note, though it always is with the odd gestures and lackadaisical expression which I have tried to describe. In other words, the beak is sometimes opened as a part of the bird's nuptial actions, and not merely with a view to the production of sound. That originally this alone would have been the motive of its being so can hardly, I suppose, be doubted, but may it not be possible that the eye has gradually come to share in a pleasure which was, at first, communicated through the ear alone, and that a process of selection, founded, perhaps, on some initial freshness of colouring, has in time produced a special kind of adornment? If this were so, we might expect that some of the birds so adorned would have the habit of opening the bill in this manner without uttering any note at all, or, at least, that they would very frequently do so. Such an instance we have in the shag, that smaller and more adorned variety of the cormorant, which is much more common on our northern coasts than the so-called common one. One of the most ordinary nuptial actions of these birds is to throw the head into the air,
