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

the World 754 The Living Animals of A comparatively small number of these moss-animals are inhabitants of fresh-water, forming brown tubular aggregations on the under side of the leaves of water-lilies or other submerged objects. It is interesting to observe that the tentacular crown in almost all these fresh-water species is horseshoe-shaped, instead of like a shuttle-cock, as in the marine forms. One very notable fresh-water species is remarkable for the circumstance that in place of horny tubes the component individuals secret a common transparent Photo by W. Saville-Kent, F.Z.S.] [Miljord-on-Sea. MOSS-ANIMALS. gelatinous matrix, which is with a creeping-base, provided . 1 hese coral-like masses are composed of many thousand closely united dwelling-cells of microscopic dimensions. wherewith the colony-stock is enabled to travel over the surfaces of the water-plants among which it lives, or up the glass sides of an aquarium. In some respects, and more especially their earlier developmental phases, the Moss-animals show affinities with the Lamp-shells, while the tentacular crown of the adult individual is closely imitated in certain worms.

CHAPTER V.

WORMS. VHE1 WORMS and their allies embrace a numerous assemblage of animals which exhibit a remarkable amount of variation both in structure and habits. A fundamental distinctionT1 which serves to separate readily even the most highly organised members of the group from the other articulate or jointed-bodied animals, such as Crabs, Insects, or Centipedes, Tribe neveris furnished by the character of the locomotive appendages. These in the Worm assume a jointed character, but take the form of unjointed membranous processes which may or may not be supplemented by bristles. Frequently bristles alone constitute the essential locomotive organs. In certain groups, such as the Leeches, Flat-worms, Thread-worms, and others, even these are unrepresented.

The appropriate title of BRISTLE-WORMS has been conferred upon the section in which the locomotive organs take the form, of bristles. Among these the COMMON EARTH-WORM is ; itincluded. At first sight the worm's body appears to be perfectly smooth and naked is found, however, on closer investigation to be furnished, according to the species, with either two or four longitudinal rows of fine, hook-like bristles. Although these bristles project but slightly above the surface of the skin, they constitute very effective aids to locomotion, enabling the animal to obtain a secure grip upon the surface of the ground over which it may be travelling. Progression under such conditions is effected, in fact, on the same principle as that of the snake, the ends of the stiff bristles with which the segments are armed fulfilling the same role as the projecting edges of the reptile's scales. Earthworms are chiefly vegetable-feeders, dragging into their holes fallen leaves, straws, and every

Worms 755

other description of vegetable debris. They also swallow and pass through their systems large quantities of earth, absorbing from it its organic constituents, and depositing the indigestible residuum therefrom in the form of "earth-casts." The useful function thus performed by it upon the surface ofworms in bringing up earth from considerable depths and redepositing the ground has been fully demonstrated in one of Mr. Darwin's works. There are some twenty species of British earth-worms, none of which, however, attain to the proportions of certain kinds indigenous to Australia and South Africa. Some of these giant species are as much as 3 or 4 feet long when unextended, and will on the stretch measure twice such lengths. Their thickness, which is proportionate, may vary from that of a man's finger to that of an ordinary sausage. The most numerically abundant and structurally varied representatives of the bristle-bearing worms are inhabitants of the sea, and are divisible into two easily recognised natural groups. In one of these the animals resemble earth-worms in their ability to move about freely from place to place. In the other group they secrete and permanently reside within a tubular edifice, which may be calcareous and of shell-like hardness, or composed of particles of sand, mud, or other sub- \ stances. The free-roving group, which embraces by far the larger number, includes such forms as the LUG-WORM, or LOB-WORM (held in high repute for fishing-baits), and a host of other allied species. In all of these the development of bristles and other appendages is more pronounced than in the Earthworms. In another group, known as the NEREIDS, the elongate worm-like body is Photo by W. Saville-Kent, F.Z.S.] [Milford-on-Sea.more Or less flattened in shape; TUBE-WORMS. unjointed leg-like appendages, Some with their flower-like gill-tufts expanded. supplemented by bristles, are developed from the majority of the segments, and the animal presents a somewhat centipede-like aspect. This likeness is further enhanced by the presence of antennae-like organs at the anterior extremity, while the mouth is armed internally with a pair of sharp-pointed, horny jaws. In many of the nereids the lateral organs are flattened out and paddle-like, constituting effective swimming-structures. Some of the larger species attain a length of several feet, and are especially noteworthy for the brilliantly iridescent tinting of their skins. The palm of beauty with respect to its brilliant colouring must undoubtedly, however, be awarded to the so-called SEA-MOUSE, frequently cast up by storms on the British coast. In this creature the body is comparatively short and thick, 3 or 4 inches long by 1^ to 2 inches wide. The centre of the back is covered in by a felt- like mass of fine interlacing hairs of a brownish hue, underneath which are broad, flat scales which protect the breathing-apparatus. The sides are, however, thickly clothed with long, slender hairs and bristles, each of which reflects the

of the World756 The Living Animals

inost brilliant prismatic tints.

The TUBE-DWELLING

WORMS are noteworthy for the elegant and often beautifully coloured flower-like gill-tuft with which the head is crowned. Its separate filaments are clothed with vibrating hairs, which create currents bringing food-particles to the mouth. In those forms which build up a hard calcareous dwelling-tube, one of the gill-filaments is usually so modified as to constitute a stopper-like organ, wherewith

Photo by If. SaviUe-Kcnt, F.Z.S.] [ M'dford-on-Sca. the animal, on retreating into SEA-WORMS, OR NEREIDS. its domicile, can effectually bar Their innumerable "false feet" impart to them a centipede-like aspect. out the ingress of intruders. In some members of the group the gill-tufts are elegantly branched and supplemented by long, simple, thread-like filaments, that are thrust out to long distances in every direction both for food and the materials required for the further lengthening and enlargement of the tube.

The LEECHES differ essentially from the Bristle-worms in the absence of bristles or supplementary appendages, in the presence of an adhesive sucking-disk at the posterior and sometimes also the anterior extremity, and on their well-known blood-sucking propensities. While the MEDICINAL and so-called HORSE-LEECHES inhabit fresh-water, some, more especially in tropical countries, infest the moist jungles and scrubs in vast numbers, and are among the alsomost actively aggressive pests with which the traveller has to contend. A few leeches inhabit the sea, preying upon the skate and other fishes. The bodies of these marine species are cylindrical, with a sucker at each extremity, and roughly corrugated or warted.

The FLAT-WORMS embrace a large number of intestinal and other parasitic species, including

TAPE-WORMS, THREAD-WORMS,

LIVER-FLUKES, and others. Among the free-living nonparasitic members of this group, the so-called INDIA- RUBBER-WORM is remarkable for the extraordinary elasticity of its tissues. Black in hue. it lives among rocks and seaweeds, and preys upon small fishes and other organisms. These, being seized by the suctorial mouth, are unable to effect their escape, the worm's body being capable of stretching out to a length of 20 feet or more, and "playing" the captured victim like a living ly W. Savillc-Kent, F.Z.S.] SEA-MICE. elastic fishing-line until it? Worms, with remarkably iridescent hairs, which burrow in the sand. struggles are exhausted.

[Milford-on-Sea, Photo by W. Saville-Kent, F.Z.S.

PORTION OF THE GREAT BARRIER REEF OF AUSTRALIA.

Showing soft or leathery and other corals, -- Photo by W. Saville-Kent, F.Z.S.)

ANOTHER PORTION OF THE GREAT BARRIER REEF.

Composed chiefly of stag’s-horn corals. This coral varies in colour, being sometimes brown with white tips, in other instances grass-green or even brilliant violet. 757

of the World758 The Living Animals

CHAPTER VI.

CORALS, SEA-ANEMONES, AND

JELLY-FISHES.

the Sea-anemones and Jelly-fishes almost the lowest WITH organised group of living animals is reached. As typified by an ordinary sea-anemone, the body may be described as a simple sac, the orifice of which is inverted for some little distance, and held in position with relation to the outer wall by a series of radiating partitions. One or more rows of tentacles, varying in number and character according to the species, surround the mouth of this partially inverted sac. There is no distinct intestinal track, the whole fliolo by W. Saville-Kent, F.Z.S.] [MHJoiti-on-Sea. space enclosed within the outer wall A MUSHROOM-CORAL FULLY EXPANDED. and ramifying among the radiating

In this condition the coral, or skeleton of the animal, is entirely concealed. partitions containing the digestive juices. The radiating membranous partitions develop upon their surfaces the reproductive elements, and in the case of Corals, which are merely skeleton-producing

-t. sea-anemones, partly secrete within E~"Ii * them the symmetrical radiating calcareous plates so characteristic of the group. Some thirty odd species of sea-anemones are indigenous to British waters, and one or more of these will be familiar to most readers. The STRAWBERRY-ANEMONE, clinging to the rocks as a hemispherical lump of crimson, green, brown, or red and isyellow speckled jelly when the tide down, and expanding like a beautiful flower when the waters flow back upon it, is the commonest and in many respects the most beautiful of all, the circlet of turquoise beads, regarded as rudimentary eyes, developed around the outer margin of the tentacles, adding a charm possessed by few other species. The DAHLIA-ANEMONE, whose expanded disk and innumerable petallike tentacles may measure as much 'avttle-Kent, F.Z.S.] [Miljonl-on-Sea. as 6 or 8 inches in diameter, is the MUSHROOM-CORALS, WITH THE ANEMONE-LIKE POLYP largest British species. These dimen- EXPANDED. sions are. however, vastly exceeded by Taken through the water on a coral-reef.