The apparatus by which they are on special occasions propelled for a short time through the air is nothing but an unusual development of the pectoral fins; but it is at least extremely doubtful whether they employ these exactly as a bird uses its wings. I have many a time observed them most carefully, but have always failed to detect any flapping motion: the fins were merely extended, and I noticed that in the direction of the wind they could move through the air for some distance, when they would fall back abruptly into their own element, as if their muscular energy was suddenly expended; while any attempt to proceed against the wind invariably resulted in failure. I am, therefore, of opinion that as they emerge from the water with considerable “way” on, the pectorals fully expanded, the wind drives them as long as the latter keep moist; so that the whole proceeding is a _vis a tergo_ rather than a flight, though it is doubtless extremely useful in escaping from their greedy enemies, much as small fry will often take to the air when pursued by a large jack. For the most part, they only rise a short distance from the water, though often sufficiently high to fall upon the deck. Illustrations of the flying-fish generally depict it as if about to mount up in the air and ascend to the altitude patronized by larks, where, in company with its fellows, it flits to and fro across the disc of the sun like a swift. I like these illustrations; they show a considerable power of imagination and not a little impudence: unfortunately, however, the flying-fish is not quite so amphibious. One variety—the _Exocœtus volitans_—has now and again been found in British waters, having presumably lost its way; or perhaps, after all, the afore-mentioned illustrations are based on fact, and the creatures have indeed flown overland from the Mediterranean, where they abound along with the flying-gurnards and similar species. Occasionally, in the warmer latitudes, the ship would be surrounded by a fleet of argonauts, or paper-nautili, which, if one excepts the fairer portion of the passengers, are quite the prettiest creatures to be seen during a voyage. The creature can easily quit the shell, which resembles in shape that of the true nautilus, not being attached to it as is the case with the majority of molluscs. Beautiful as the creature unquestionably is, yet it reminds one of the hideous octopus, in that both are provided with a number of tentacles, two of which, dilated to a circular membraneous expansion and raised above the water, bear a decided resemblance to sails, while the others, which move under water, suggest the action of oars. Hence arose the idea, which, still prevalent at the time of which I am writing, has only been combated comparatively recently, that they actually sailed and rowed about.