Photo by W. Saville-Kent, F.Z.S.] [Milford-on-Sea.
SEA-WORMS, OR NEREIDS.
Their innumerable "false feet" impart to them a centipede-like aspect.
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 the animal, on retreating into its domicile, can effectually bar 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 most actively aggressive pests with which the traveller has to contend. A few leeches also 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.
Photo by W. Saville-Kent, F.Z.S.] [Milford-on-Sea.
SEA-MICE.
Worms, with remarkably iridescent hairs, which burrow in the sand.
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 non-parasitic 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 elastic fishing-line until its struggles are exhausted.