By the deep sea

I would strongly advise my readers to catch a full-grown Prawn, kill it by immersion in fresh cold water, cut the body through at the junction between the helmet-like carapace and the first plate of the abdomen, when the entire contents of both head and body can be cleaned out, and the space filled with white cotton-wool. When thoroughly dry the two parts may be reunited by a mere touch with Lepage’s Liquid Glue. It would be well to do this in duplicate, and whilst still fresh to take one specimen to pieces, and mount the various appendages on a white card, gumming them down in their natural sequence. Leaving the pear-shaped eyes where they are, we commence with the first or internal antennæ, which we shall thus see has its basal joint spread out into a broad scale which ends in a sharp spine at the side of the second joint. It is in this basal joint that the Prawn’s organ of hearing is contained. Spence-Bate and others have investigated this remarkable organ in various species, and find there is a little chamber with a slit-like opening, only to be seen when the creature has just shed his coat of mail, at which time he picks up with his “finger and thumb” a few minute grains of sand and carefully introduces them into this auditory chamber, where they mix with some fine hairs or cilia, and their agitation when acted upon by sound-vibrations transmits sensation to the nerves. The third joint gives support to two lashes or “horns,” one of which in this species is branched.

The basal joint of the second antennæ also bears a flattened scale that is enormous, being three-quarters of an inch in length and a quarter of an inch in breadth. There is but one lash (flagellum) to this external antenna, and this strong, long organ measures over six inches in full-grown specimens; that is, one and a half times the extreme length of the Prawn from the tip of the forbidding rostrum to the extremity of the tail.

We have mentioned the two pairs of “hands” (chelæ), and behind these are three pairs of long and slender walking feet. Then, further back, beneath the abdomen, there are five pairs of swimming organs, and to these in the female the eggs are attached. The tail-fan must not be forgotten; it is a beautiful and most effective organ. The four plates of which it is composed are finely fringed with delicate hairs, and are so hinged that they can be partially closed one over the other, or fully expanded to have greater power when opposed to the water. It is by means of this valuable organ that the Prawn takes those astonishingly rapid backward leaps which make him hard to be caught either by man or smaller enemies.

Before leaving the Prawn, I would like to say that our portrait of him does not pretend to show the length of his antennæ; and it would be well to make clear how he carries so many to be useful to him. He is always waving these about, and there can be little doubt that he receives impressions through their agency, olfactory and otherwise. It does not matter how far away a Prawn may be; if you give an anemone a small portion of food, and there is a Prawn at the far end of the tank he will know it, and will come prancing up to the right neighbourhood. But his olfactory sense though it helps him to this extent, appears to act best at a little distance from the fragrant object. I have frequently observed a Prawn come quickly to the locality where food has been introduced and evince great excitement and interest; but his sense has not been fine enough to tell him at once the particular spot in the locality where it lay. I have on such occasions seen him walk over what he was seeking, whilst his hands were nervously scraping the ground and casting around for the delicacy he knew was close by. Now this is the order of his antennæ-bearing: of the first or internal antennæ that lash which has the short branch is carried half erect pointing outwardly, the companion lash pointing forwards, so that he cannot run against any obstruction without knowing it. The second or external antennæ are borne with a slight curve forward, then far abroad on either side. He is thus fairly guarded by sensitive organs well-nigh all round.

There are two other British species of Leander—L. squilla and L. fabricii—which occur in the rock-pools, and may easily be mistaken for young specimens of L. serratus. The distinguishing feature is to be found in that awe-inspiring, saw-edged rostrum that projects far in advance of the Prawn’s head, and of which no one has yet discovered the purpose. In the bona fide Prawn this has a very decided curve upwards all the way, and on its upper edge it has seven sharp spines closely following each other, with an eighth lagging a sixth of an inch behind the seventh, and really on the carapace, not the rostrum; on the underside there are four close together in the middle, and a half-hearted one midway between the first of these and the tip of the rostrum. So much for the type; now for L. squilla. The rostrum is almost straight with a slight upward curve towards its tip. Like its big relative it has seven or eight teeth above, but two of these are really part of the carapace, and there are only three spines below. The second pincer-legs are not proportionately as robust as in the Prawn, and the creature does not attain to more than half the Prawn’s dimensions. L. fabricii has the rostrum nearly straight, with five teeth above and three beneath; in addition, this species has the rostrum covered with a multitude of minute reddish dots. There are similar dots in the Prawn, but none in L. squilla, with which it agrees more closely in size. These two, with young specimens of L. serratus, get mixed up and sold together under the name of Red Shrimps or Cup Shrimps.

There is a somewhat similar form called the Æsop Prawn (Pandalus montagui). It may be distinguished by the fact that the carapace is distinctly keeled along the foremost half of its upper part, and this keel is continued forward as the rostrum, which is armed above with moveable spines, while below it has five fixed teeth. The outer antennæ are long, and marked throughout by alternate light and dark bands. The inner antennæ have two lashes, the outer of the two thicker than its fellow. The first pair of legs are not furnished with nippers; and the second pair are very unequal in length and stoutness. It is reddish-grey in colour, dotted with a darker tint. Its length on our shores, according to Bell, does not exceed two and a half inches; but on the coasts of the United States it is said to attain to a length of four or five inches.

There is a beautiful little Crustacean, which may fitly be named the Varying Prawn (Hippolyte varians); it swarms in certain rock-pools and among the rocks at low-water. In such situations it is not so widely distributed as some of the species we have named, but it is worth looking for on account of its remarkable sensitiveness to the colour of its surroundings. Specimens taken from a pool in which the green Ulva or Enteromorpha is the prevailing vegetation are green; but if transferred to a vessel containing only brown, red, or yellow weeds, will in the course of a few hours be found to have changed their colours to harmonise with their new environment. So complete is this change that one can well understand how this shrimp may be commonly distributed all round our coasts, and yet only known from a few localities, because a careless observer would never see it. Like the species of Leander this has a rostrum—in this case quite straight, a sharp point. On the upper edge there are usually four teeth, but this number may be increased to five or even six; on the underside they never exceed two, and there may be only one.

Whilst referring to these little-known species of Prawns, we must not forget to mention the very well-known Common Shrimp or the Shrimp (Crangon vulgaris), which affects sandy shores and rivers rather than rocky coasts. The natural colour of the Shrimp before it has been in the pot and made to reappear as the Brown Shrimp, is a pale brownish grey, thickly dotted with darker brown, which harmonises well with the sandy flats on which it loves to live. Looking at this species we see how great a finish is given to the Prawns by the possession of that saw-edged rostrum. By comparison the Shrimp has a square front, which is by no means so prepossessing. His eyes are not so distant one from the other as are those of the Prawn, and only one pair of his antennæ (the external) are at all long. There are three small spines on the carapace, one on the middle line and one on each side. The first pair of legs are stout, and what is technically described as sub-chelate, those of the Prawn’s being chelate. The Shrimp’s nippers have not got the well-formed moveable finger and fixed thumb of the Prawn, but a moveable finger and a little stump upon which it folds down. I do not pretend that it is not as efficient for the Shrimp’s use as the better-looking contrivance of the Prawn. The plates of the tail-fan, too, are narrower than those of the Prawn, but the swimming feet are longer.

Now these two things would lead us to suppose that the Shrimp depends less on jumping back from danger than on swimming, and this is true. If the Shrimp suspects harm he sinks upon the sand, and setting his swimming feet rapidly to work they “kick up such a dust” in the water that he is hidden in a cloud of fine sand, which as quickly settles down and partially buries him—sufficiently so with his sandy hue to effectually hide him. Upon those swimming feet the female carries her eggs. From the fact that shrimps may be found laden with these eggs at almost all seasons, it would appear that they have no special breeding time; and this fact probably accounts for the endless supply of them. In common with most other small Crustacea they are constantly preyed upon by fishes, and we know something of the enormous mortality among them caused by man, when we think of the heaps in the fishmongers’ shops and in the baskets of the itinerant vendors in towns. But the united efforts of man and fish do not appear to make them at all scarce.

There are quite a multitude of distinct species of British shrimps, but many of them keep away from the shore and are only caught in the dredge or the trawl. Some others swarm after the bait in lobster pots, though the lobster catcher does not want them, and does not even dignify them with a name—scarcely notices their existence, in fact. There remain, however, several species to which I must call attention, even though my readers may have expected me to have exhausted the list long before this.

The Chameleon Shrimp (Mysis flexuosus) will be found in summer to abound around the rocks and in the pools. It partakes somewhat of the character of Hippolyte varians in respect of colouring. If you take it around rocks that are covered with the Laminaria it is pale brown, or darker if from among Fuci, and in the pools where Ulva, Enteromorpha, and Cladophora prevail, its colour will be a light or dark green. It is a singular-looking shrimp on account of its long and slender carapace and the cylindrical abdomen. It has six pairs of feet, and not one among them all possesses a pair of pincers. The external antennæ are very long, and each is accompanied by a long flat scale similar to that of the Prawn’s. The eyes are large and very prominent. The carapace is inclined to have a rostrum, but it is a poor attempt, and does not extend to more than a third of the eye-stalk. It is sometimes called Opossum Shrimp, because it has a peculiar pouch in which the eggs are retained until hatched, and where the young pass their early days.

There remain several species which should more fitly be included with the Lobsters, but from their small size they may pass muster with the Shrimps. They are exceedingly interesting, even if we take but one fact into account: their habit of burrowing in deep sand like mole-crickets. Right back in the early days of the present century an enthusiastic naturalist, Colonel Montagu, was digging for Razor-shells (Solen) in a sandbank near Kingsbridge in Devonshire, when he had the good fortune to turn up some things he was neither looking for nor suspecting the existence of—as a matter of fact they were quite unknown until Montagu unearthed them. Now here is encouragement for anybody and everybody who turns over weeds, pries into rock-pools and crannies, or digs in the sand for Launce or Razor-shells. You may or may not find what you seek, but something of interest you cannot help finding, and it may be a new fact—if not a new species.

When Montagu published a description of his find in 1808—three years afterwards—it was under the three-barrelled name of Cancer Astacus subterraneus; but Dr. Leach, six years later, saw that it could not go into the same genus with the crabs or lobsters, and he called it Callianassa subterranea, by which name it has been known ever since. So far the account is plain sailing enough, but to attempt a description of Callianassa is not nearly so simple. The carapace is very small, with the slightest pretence to a rostrum, flattened at the sides, rounded above. The eyes very small, like those of its fellow-digger the mole, though more exposed than his. There are two pairs of antennæ; the internal ones double. The first legs are adorned with nippers, but they are very unequal in size, one being scarcely larger than the second or third feet, and the other much larger than the carapace, broad, flat, and hairy on the edges. On the outer side of the arm of this big limb there is a process which looks like a reaping hook. Now, the word Callianassa, I presume, is made up from two Greek words (Kalli, anassa), signifying Beautiful Queen; but I fancy that if a female monarch had one of her hands normal and the other bigger than her chest and head combined, none but courtiers would flatter her by declaring she was beautiful, and possibly they might be partly actuated thereby through a wholesome fear of that big hand. However, she is beautiful in respect of colouring—a fine bright pink, which departs with life. The second pair of legs are small and terminate in a little pair of pincers; the third have one finger which works against the enlarged next joint; the fourth terminate simply in a claw; the fifth in an intermediate condition as though the extremities intended to develop into pincers. The seven-jointed abdomen is long, the fifth segment broadest, from which it narrows gradually to the front, and suddenly to the rear, where it is finished off with a tail-fan of four plates. From a glance at the Beautiful Queen’s hands and with knowledge of her burrowing habits, I should suppose that the bigger of the two served the double purpose of a digger and a street-door; the latter to keep enemies and prying intruders out of her burrow. Her majesty measures about two inches in length, and her crust is very thin and parchmenty.

That was a day to be remembered by Colonel Montagu, for on the same occasion he unearthed another burrower—Upogebia stellata—new to science. This is more lobster-like than Callianassa in form, though less so in size, for it is only about an inch and a half in length. It is content with having pincers to the first pair of legs, and these are nearly equal in size. All the limbs are liberally fringed with long hairs. The carapace begins with a small and sharp rostrum. Dr. Leach records it from mud in Plymouth Sound. Its colour is yellowish-white, sprinkled with minute orange spots.

And now, though we have by no means exhausted the list of British species, we must close this chapter. It should be stated that all these creatures go through a series of transformations similar to, but not identical with, those marking the early life of the crab and lobster.