Part 23

AUGUST.

What eager pursuer of marine animals has not gloated over a rock-pool? On all our rocky coasts we find them more or less developed; but it is on these south-western shores, where the compact limestone juts out into promontories, that we find them in perfection. The burrowing mollusca specially favour the limestone; the Saxicava, I think, lives in no other medium; and it is to the operation of this coarse ugly little shell-fish that this rock is indebted for the honeycomb-like excavation which has eroded its surface. Below a few inches this erosion does not extend, for the Saxicava is but a small animal, and its siphons must reach the orifice of its burrow; therefore it never goes deeper into the stone than will allow it comfortably to bathe its red nose in the free water, though it is not at all particular about the angle to the surface at which it bores. The myriads and myriads of these auger-holes that have been bored remain, though the feeble animals perish generation after generation; each new-born shell-fish makes a new bore for itself, never appropriating one ready-made, and so there is a perpetual excavation of the living rock with these shallow auger-holes, always of the same width, or nearly; about half-an-inch. The result is what we see; that the surface of the rock knows no such thing as a plane surface, but a surface covered with smooth borings, running in all directions, so as continually to break in on one another; and that so close together, that the interspaces form narrow knife-edges, and sharp angles and projecting points. A particularly interesting circumstance is, that this honeycombed condition is characteristic not only of that level of the rock which is covered by the sea for some portion of every tide, but of that part, to a certain height, which is never covered at all. The Mollusca, it is true, cannot live wholly deprived of sea-water, and, in fact, there are none in this ever-dry portion, though the burrows by thousands testify that they were there once. We must infer that the coast has been generally elevated; perhaps by slow and imperceptible degrees, by an operation still proceeding but unappreciated; perhaps by some sudden convulsion which took place at a remote era, unrecorded and forgotten.

HOW ARE ROCK-POOLS MADE?

When once raised beyond the level of the highest tide, the eroded surface appears to have a permanency which defies the action of the elements for an undefinable period; for it seems liable to little change. It is probably comparatively unalterable, or alterable slowly, beneath the level of the lowest tide. But between tide-marks, the perpetual change from wetness to dryness and back again, and the incessant wash of the waves, which frequently beat and dash upon the eroded surface with immense violence, are continually grinding down the projecting points and thin walls of stone, and thus creating a new surface, to be bored afresh by new generations of Mollusca.

It has seemed to me that these burrows have played and are playing an important part in the formation of the numberless rocky basins which we call tide-pools, and in which we marine naturalists so much delight. Let us look at the process. About half-tide level there is a mass of bored rock, from whose burrows the tenants are dying out for want of sufficiently long water-covering. A heavy sea is breaking over it, which has snapped off the thin partition beneath two contiguous burrows, breaking it into several sharply angular bits, which fall into the hole. The whirling and eddying of the waves rattle and roll these fragments round and round day after day, week after week, till at last they are ground to nothing: but an equal effect has been produced on the hollow which held them; its cavity has been widened and deepened by the same grinding action. By-and-by a pebble is rolled in, and being almost large enough to fill the cavity, it does not readily wash out, but grinds round and round with the motion of the sea. So the process goes on, perhaps for centuries, perhaps with long intervals of almost sameness; every stone that is washed-in enlarging the work; while, when once the hollow has become only ever so little larger or deeper than those which surround it, the pebbles will have an increasing tendency to roll in and to stay there. So, at length, the basin is formed, tiny at first;--I know scores not so big as a slop-bowl, which yet have their furniture of elegant little sea-weeds, green and purple, and their tenants of worms, and shrimps, and polyps;--but destined by-and-by to become noble reservoirs in which man may pleasantly bathe, and in which little fishes play and shoot to and fro, and hide under the umbrageous fronds of the oar-weed and tangle that droop gracefully into the ample cavity.

CORKWING.

In the pleasant sunny afternoons of this season of the year we may find in tolerable abundance the pretty Cork-wing, in such rock-pools as I have been speaking of. In the shallow hollows of the ledges they shoot hither and thither, the swift movement just catching the collector’s eye; but here they are difficult to capture, owing to the numerous exits and hiding-places among the stones. The deeper basins are pretty sure of containing one or two, and generally of larger size. Here the dip-net can be brought into action, and they are readily taken. But the finest specimens are obtained around the edges of the rocks in the free water, and where there is considerable depth. Here the attentive eye discerns them quietly hovering, some yard or two beneath the surface, deliberately picking their tiny crustacean food from the drooping weeds, or playing to and fro in little parties of half-a-dozen, on motionless or gently undulating fins; a pretty sight to watch. From these seaward edges of the rocks the coarser sea-weeds growing in a thick fringe, when the tide has left them partly exposed, hang their tips in the heaving water; and under this grateful shelter the little Corkwings, as well as other small fishes, their companions, delight to disport themselves, finding copious food in the purple obscurity, and getting many a peep through the latticed leaves at their idler fellows in gamesome play without. If, now, the collector have provided himself with a stiff ring-net, and a long and stout handle, he may sift out, as it were, the tenants of these shades, by collecting, in succession, the drooping weed-tips in the mouth of his net, and lifting it gently through them; when the lovely little emerald fishes will be found, two or three at each dip, struggling and panting and leaping and quivering their helpless fins at the bottom of his bag.

PLATE 22.

P. H. GOSSE, del. LEIGHTON, BROS.

CORKWING WRASSE. ]

The Corkwing belongs to the great Wrasse family; which, though it chiefly develops itself in the tropical seas, is yet well represented in our own. Yarrell has figured thirteen species, all of them found on our south-western shores, and a few of them ranging to the north as well. The entire family is remarkable for its bright and gorgeous hues, often taking the form of bands, stripes and spots, well defined, and in vivid contrasts. This little species, which extends to the length of five inches, but is much more commonly taken not more than half that size, is of a rich emerald-green hue, lighter beneath, and generally marked with a conspicuous black spot on each side of the base of the tail. Small individuals are frequently found, of a dark reddish brown, arranged in a minute tesselated pattern on a pale ground; and occasionally of a rich golden bronzed hue. The eyes are usually of the finest vermilion.

FIGURES OF WRASSES.

They are entertaining inmates of an aquarium; they play slowly up and down in the corners of the tank, exploring every angle and cranny, hanging in every possible attitude, especially at night. They soon become familiar, and may be preserved in health a long time. They are constantly occupied in searching for, and picking off atoms, invisible to us, with their protrusile lips. These organs are remarkably large, thick, and fleshy, whence has been derived the name of the family, Labridæ (from labrum, a lip); and, in death, they are generally projected in an uncouth and repulsive form. It is a pity that Yarrell’s figures have been for the most part copied from specimens in this distorted condition, and are therefore hideous caricatures of the little beauties. His Corkwing is a notable example, presenting but little resemblance to the playful emerald in my tank; while the Gilthead and the Sea-wife are still more horrible. It is matter of regret that so large a portion of our pictorial natural history represents death rather than life; while a herd of slavish compilers, who have never seen the creatures on which they obtrude their teachings, copy such imperfect figures, and copy each other, and go on augmenting the distortions, and straying farther and farther from nature, till all vraisemblance is lost in the ludicrous caricature.

In a former work I have narrated the untimely fate of one of these pretty fishes in my possession, through the poison-darts of a Parasitic Anemone. A similar accident befell one lately, which I had kept in my tank for about two months. This individual, about two and a half inches long, active and healthy, made a backward spring, and came in contact with the tentacles of an Anthea cereus, which in an instant enveloped its hinder half, clinging round and over it and quite covering that portion. I was looking on, and after a moment’s glance to see that the fish was perfectly helpless, I removed it with a stick, so that it was free in about half a minute from its accident. But the effect was manifest; it swam away indeed, but irregularly and fitfully, and presently sank down on the bottom; lay awhile, then struggled up for a few seconds, swimming on one side, as if partly paralysed, and frequently turning over belly-up; then sinking obliquely down and hiding its nose between the stones. The fins were white and ragged, and the skin of the hinder part was ruffled up in parts, and the entire hind-half looked diseased. By night it was not to be seen; but the next morning I found it, dead and stiff, and with the whole of the parts that had been embraced by the Anthea turned of a pellucid white, the edges of the fins sloughed away and decomposing.

When we consider that the entire period of contact was no more than half a minute, the power of the subtle poison, injected by the cnidæ of the Opelet, becomes very manifest; and the accident afforded me another confirmation of what has been fondly denied, the amazing energy of the poison-apparatus in the ACTINOZOA.

LUCKY PROACH.

An assiduous searching of these hanging fringes of fuci will be sure to yield a pleasing return of other objects. Neglecting at this moment the Prawns, Æsops, Opossum-shrimps, Spider-crabs, and many other crustacea, not to speak of other classes, let us direct our thoughts exclusively to the fishes. You will get probably one or two specimens of that little bull-headed rogue, the Father-lasher, armed at all points, like a knight in the fair time of chivalry. An impudent little rascal he looks, and right villanous; but whether he is in truth guilty of whipping his paternal parent, this deponent saith not. Big-headed, wide-mouthed, staring-eyed, beset on all sides with hard spines as sharp as needles, which he erects with threatening fierceness as he anticipates your touch, this Lucky Proach, as our northern friends name him, may not invite a close acquaintance; and indeed our fishermen generally jerk him energetically out of the net as soon as they see him, thinking themselves “lucky” to be well quit of his prickles.

PLATE 23.

P. H. GOSSE, del. LEIGHTON, BROS.

FATHER-LASHER. WORM-PIPEFISH. ]

ITS HABITS.

Yet in truth he makes a funny little tenant of the aquarium. His colours are agreeable; deep rich brown on the upper parts, fantastically patched and clouded with various shades from black to pure white, while the sides and belly are brilliantly silvery or opalescent. His countenance expresses considerable intelligence; and the contrast between his aspect when he is alarmed, and all his spines are laid flat, and when he thinks to carry his point by bullying, and bristles up all his sharp lances, and glares with a threatening goggle, is very amusing. He presently becomes at home; for a day or two he skulks under the rocky ledges, and you see little of him; but soon his characteristic impudence reassures him, and vires acquirit eundo; he makes short hasty sallies into the open, and instantly scuttles back to his retreat; presently you see his great head projecting out of some crevice in the rocks, whence he can command a pretty extensive view; and now that is his selected home, and there henceforward you may pretty surely find him, whenever he is not to be seen engaged in predatory forays in some other quarter of the tank. Now he grows very saucy; not a Blenny or Goby or Pipe can come before his castle-gate but Proach must dash out to have a passage-of-arms with him, returning, in all the pride of conquest, when he has driven the routed foe out of sight, to his rocky fortress, and settling himself in the same watchful attitude as before. Every atom of meat that you drop into the water within his range of vision must be his: you perhaps intended the morsel for the Goby or the Blenny, but Proach sees it, and Proach must have it. They indeed may sail up towards the speck, but Proach dashes up, bristling with indignation at their temerity, and snaps the food from before their very noses. Not one of them can get a bit till Proach is satiated; and I have often seen him lie with a morsel projecting from his mouth for some time, absolutely incapable of swallowing more, before he would relinquish the contest. Now he fears nothing; he will even rush to the surface when he sees you approaching, and, with a sudden snap, seize the meat in your fingers, and drag it away.

Mr. R. Q. Couch gives us some interesting particulars of this little fish, or his brother, the Sea-scorpion; for they are so much alike, both in appearance and manners, that some naturalists do not recognise any specific difference between them. “When caught,” he says, “it makes a croaking kind of noise; opens its gill-covers, and erects the spines of its head, and stiffens its whole body, as if prepared for a vigorous defence. The spines are covered with a skin or sheath, which the creature has the power of drawing from the points and leaving them bare. This fish will live a long time out of water, provided it be kept slightly wet, but soon dies on immersion in fresh water. Those fish that swim deeply are able to sustain life much longer than those that swim near the surface; and the former are more sluggish in their movements, and require less aërated water for respiration. The more active are surface-swimmers. The immersion in fresh water acts as a poison, death not resulting from any variation in the respirable quality of the water. If a Sea-scorpion, after being taken from the sea, be constantly kept wet with salt water, it will live for a considerable time, the gill-covers acting as if surrounded by water. If the gills be kept wet and the skin dry, the creature gets restless, croaks, the gills move less rapidly than before, and it then dies at an earlier period than when kept altogether moist. If the gills be wetted with fresh water well aërated, life is not so long retained, but the fish seems more active for a time, and dies at last almost in a state of plethora.”

According to Yarrell, “this species spawns in January, and the ova at that time are very large and of a fine orange-yellow colour. These are deposited near the sea-shore, frequently in the estuaries, and sometimes even in rivers; the fish having prepared itself for this change by its previous residence in the brackish water, after which it appears to be able to bear either extreme. Its food is small crustaceous animals, and it is said to be particularly partial to feeding on the fry of the Blennies.”

RESPIRATION OF FISHES.

On the subject of its instant death, when removed from its native element to fresh water, the same naturalist remarks, alluding to the hypothesis that the speedy death of fishes in general, when removed into the atmosphere, is due to the drying of the delicate membranes of the gills; “the reverse of desiccation takes place in this instance: the gills are bathed with a fluid containing more oxygen than sea-water, and which also yields that oxygen much easier, yet death happens immediately. In this last instance it may be inferred that the fish, unable suddenly to accommodate its respiratory organs to fluids of such different densities as those of pure sea and fresh water, the blood is imperfectly aërated, the brain is affected, convulsions ensue, and if not released it soon dies.”

You will pretty certainly find in your net, too, twining and writhing about like little snakes, some of the smaller species of Pipe-fishes, often called Sea-adders, and most abundantly the smallest of them, and the commonest in shallow waters,--the Worm Pipe. The pretty Æquoreal Pipe, or as Mr. Couch appropriately names it, the Painted Sea-adder (from the variegated tints of brown and yellow, wherewith its numerous angular plates are individually adorned), is abundant enough all along our southern coast, in deeper water, affecting the extensive beds of zostera, and of sea-weeds, which in many places clothe the bottom. The eminent Cornish zoologist observes of this species, that “in May and June, and frequently in July, and occasionally in August, these fish rise to the surface of the water, however deep it may be, and bask themselves in the sun. They retain their position at the surface by clasping with their tails the cords and buoys of the crab-pots, sticks, or any other substance they may find floating at the surface. The whole of the caudal portion of the body is coiled round the stick or cord, and the heads lie either horizontally or at right angles to the surface. In some seasons the buoy-ropes of the crab-pots are literally obscured by them from the surface of the water down as far as the eye can penetrate.”

PIPE-FISHES.