The Living Animals of the World, Volume II: Birds, Reptiles and Amphibians, Fishes, Jointed Animals, Molluscs, etc.

of the World668 The Living Animals

late Matthias Dunn of Mevagissey seriously urged on the Admiralty to dynamite them in the.interests of the fishing industry. Most of the sharks deposit their eggs in the curious oblong vessels known by those who pick up the disused cases on the fore- _^^fi shore as purses; and ^^C " " "-. these attach themselves to.^^ .-J| ^,-;* rocks and stones by long tendrils that cling to every ^^ W0|^ support. A number of species (the PORBEAGLE and TOPE among British kinds), however, bring forth their young alive. Between the Sharks and Kays there is a curious and _MUjord-on-lSea. interesting link in the form HORNED OX-RAY, Oli DEVIL-FISH. of the MONK-FISH, or ANGEL- This species and its allies attain enormous proportions. One taken at Barbadoes required seven FISH, which is common on yoke of oxen to draw it. all sandy shores, and a frequent victim of the trawl. Such local names as Mongrel-skate and Shark-ray indicate a widespread acceptance of its intermediate position between the two groups under notice. Like some of the sharks already noticed, it produces living young, and its maximum size may be set down as at any rate over 7 feet. The writer measured and weighed one trawled in Bournemouth Bay during the summer of 1896. Its length was nearly 4 feet, and its weighl rather less than 50 Ibs. Like many of the rays, this species feeds to a great extent on flat-fishes. In outward form the monk-fish, though it is in reality more nearly allied to the sharks, brings us by an easy transition to the flattened RAYS, with their long whiplike tails and pointed snouts. There are a dozen, or rather more if we count casual visitors, of these skates and rays in British seas, the largest being the great EAGLE- RAY, examples of which have been recorded of the enormous weight of 1,000 Ibs. Many of the smaller kinds are Studded With Sharp Spines, Pliotopii0toiyby Wfw.samiie-Kent,F.z.s.]SavUU-Kenl, F.Z.S.l [MUford-on-Sca. curved in some species, and WHIP-TAILED STING-RAY. the THORNBACK owes to these Sting-rays are abundant in tropical seas.

Sharks and Rays 669

its trivial name. All these rays, in fact, have some form or other of formidable offensive and defensive apparatus. The STING-RAY has on its tail a fearful serrated dagger, 6 or 8 inches long in large examples; while the TORPEDO-or NUMB-FISH has electric organs in the head, with the aid of which it can give a shock sufficiently strong to paralyse the fishes on which it feeds. Two interesting peculiarities of the rays deserve notice in concluding this chapter. The first is that their egg-purses, instead of fhulo by W. aamUe-Kent, F.Z.S.] [Alilford-on-Sea. attaching themselves with SHOVEL-NOSED SKATE. tilaments to weeds and rocks, Known also as the Halavi Ray. like those of the sharks, are provided with a sticky secretion which answers the same purpose of anchoring them in security from currents that would carry them out into deep, cold water. The second is the sexual difference in the teeth, which are pointed in the male and flat in the female. bills ofWhether this difference in the teeth (which may be likened to that between the the male and female Huia-bird of New Zealand) indicates a corresponding difference in food, is an interestingor, on the other hand, some co-operation between the sexes in procuring it, question that our present slight knowledge of the habits of these fishes does not enable us to answer. Finally, attention must be drawn to the remarkable transformation which the breast-fins and tail have undergone. The j 1:3$% f rmer have developed into powerful swimming-organs, locomotion being effected by their undulatory movements, instead of by similar movements of the whole body, or by side-to-side motions of the tail, as in other fishes. Whilst the latter, no longer used in swimming, has either been reduced to a mere vestige, as in the HORNED OX-RAY, or has become developed into a long and tapering " whiplash," provided with a poison-spine. In such cases the long tail is used to encircle prey, and at the same time to force PAINTED SKATE. the victim on to the deadly So called on account of its conspicuous coloration. Spine.

BOOK V. JOINTED ANIMALS.

CHAPTER I.

THE CRAB AND SCORPION GROUPS.

BY W. F. KIRBY, F.L.S.

section of animals is often called a " sub-kingdom," and differs from back-boned animals in having the framework of THIS the body outside. That is, instead of a skeleton, Crabs, Spiders, Centipedes, and Insects are protected either by a hard shelly casing, or by a tough skin, to which the muscles are attached; and this less susceptible arrangement renders them much stronger and much to injury, in proportion to their size, than vertebrate animals. They have cold blood, generally of a white colour; and their bodies and limbs are usually composed of a considerable number of

.. separate joints... The group is a very large one, and it is probable that there are at least 300,000 different kinds of insects already known, while the total number of species now existing is estimated by different entomologists as from two to ten millions. It is, therefore, no exaggeration to say that every word of our brief account of the Insects

! represents from ten to twenty J known species at least. The

Photo by E. Connold. other classes of the group are

BARNACLES. also very numerous. Our must necessarily be ^t short; the characters of very the principal classes of the Jointed Animals are referred to in their places.

CRABS, LOBSTERS, SHRIMPS, WOOD-LICE, BARNACLES, ETC.

Jointed animals are generally provided with one pair of long jointed organs, called "antennae," a naturalised word derived from the Latin, in which language antenna means a sail-yard. They are often called "feelers," and usually fulfil this function at least; but they are also frequently organs of smell, and sometimes probably of Photo by W. P. Dando, F.Z.S., Regent's Par hearing and other senses. One peculiarity of the CRAB A PAIR OP BARNACLES. and LOBSTER group is that they are generally furnished The larger size of this photograph exhibits structural details than the last.with two pairs instead of one pair of these organs. 670

Crabs, Lobsters, Shrimps, Wood-lice, Barnacles, etc, 671

They are nearly all aquatic animals, by far the larger portion being marine, and they breathe with gills. They are provided with a hard calcareous or horny covering. The head is not separated from the trunk, as in insects; and they are provided with a number of jointed organs, usually classified as three pairs of jaws, three pairs of foot-jaws, and five pairs of legs in the more typical families; but in the smaller and more is more variable. aberrant species the number In their early stages they frequently pass through very extraordinary changes of form, but after assuming their adult shape they grow by casting their shells at intervals. We will now notice a few typical

Photo by W. P. Dante, F.Z.S.] [Regent's Park. examples of the different groups of these ACORN-BARNACLE. creatures. The general appearance is so different from the Stalked Barnacle that it is The BRINE-SHRIMP is a little reddish difficult to believe the two belong to the same group. creature about half an inch long, which prefers the concentrated solution of brine-pits to sea-water. It has eleven pairs of legs, and, notwithstanding its name, the front portion of its body is considerably broader and flatter in proportion than that of a real shrimp, the other half consisting of a jointed tail.

BARNACLES were formerly considered to be shell-fish, but are now usually classed with the crabs and lobsters, because, when they are young, they appear as freely swimming creatures, fixwith one eye, two antennas, and six pairs of jointed limbs. When they grow larger, they themselves to a rock or some other object by the head, and develop a shell, usually composed of several pieces. The commonest is the ACORN-BARNACLE, the white shell of which, measuring rather less than an inch across, swarms on rocks at the seaside. It is shaped like a limpet, but open at the top. The GOOSE-BARNACLES hang down by a stalk, and their jointed shells more resemble those of a mussel than that of a limpet, though they are composed of several pieces. Various species similar to both those mentioned are found on piers, rocks, the bottoms of ships, and even sometimes on the skin of whales.

In dark cellars in the country, under loose bark, or under pieces of wood which have been left in the fields, we often see creeping about brown creatures about half an inch long, with jointed bodies and antennae, and short jointed legs. They are called WOOD-LICE, and several species roll themselves up into a ball when alarmed. These creatures feed chiefly on decaying vegetable substances; and is commonthere is a larger marine species much like them, which in holes and crannies in the rocks on the seashore.

There are other curious creatures, called WHALE-LICE and FISH-LICE, which are parasitic in their habits. Some of these look like spiders, and one or two have enormously long legs; but others are of strange and almost indescribable forms, and sometimes without legs at all. One species, found on the sprat, has two long appendages at the end of its body not unlike a pair of compasses. F.Z.S. W. P. Dando, SHRIMPS and PRAWNS are red when cooked, but when alive Photo by Park. Regent's are very pretty semi-transparent objects, which may be seen WOOD-LOUSE. swimming about through the glass of aquariums placed against A land representative of a numerous the wall. Prawns are larger than shrimps, and have a strong marine group.

serrated spine in front of the head. Shrimps and prawns, of which several kinds are found off the British coasts, generally prefer shallow water, with first two a sandy bottom. In most of these the pairs of feet are divided to form a pair of pincers at the extremity; but in such small creatures this is easily overlooked, unless special attention is directed to it. It is different with the LOBSTERS and CRAYFISH, which much resemble shrimps in form, but are very much larger, and armed with a pair of very large pincer-like claws, in addition to the other legs. Lobsters live in the sea, in holes in the rocks, into which they dart backwards, and there protect themselves with only the head and claws projecting at the opening, ready to face any intruder. Crayfish, which are smaller, live in holes in the banks of brooks and rivers. There are many species, some of large size and bright colours. The COMMON LOBSTER is black when living, but other species are red, blue, or variegated. Sometimes, if we pick up a whelk-shell on the beach, we shall find it inhabited, not by a mollusc, but by a crab, with its legs and claws wedged 1'hoto by W. P. Dando, F.Z.S.] [Regent's Park. together, so as to fill the aperture completely SHRIMP. one claw, much larger than the other, resting in A species which plays an important part in the food-supply front; and if we pull it out, we shall find that, of London. though the front of its body and the legs and claws are hard, like those of an ordinary crab, it has a long, soft, fleshy tail, absolutely defenceless and unprotected. Crabs belonging to this curious section are called HERMIT-CRABS, and protect themselves by taking possession of shells which they have either found empty or appropriated by the easy and economical process of devouring the owners. The few species found on the British coasts are all small, and more frequently noticed in whelk-shells than in any others; but tropical species attain to a considerable size, and may sometimes be found in shells measuring 3 or 4 inches across at the opening. Crabs are distinguished from the lobsters by their compact form, and by having the short tail turned in under the body. There are a great number of species, differing much in size, shape, and appearance. One of the best is theknown in England large EDIBLE CRAB, which may often be seen in fishmongers' shops, and, unlike the lobster, Photo by C. N. Uam-oymi\ [Smyrna.does not Change much in FRESH-WATER CRAB. colour when boiled. Every visitor to the seaside must In general appearance very similar to the common shore-crab.