756 THE LIVING ANIMALS OF THE WORLD 



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SEA-WORMS, OR NEREIDS 



Their innumerable '■'■ fahc fect^^ impart to them a centipede-like aspect 



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most brilliant prismatic 

 tints. 



The Tub e-dwelling 

 Worms are noteworthy for 

 the elegant and often beauti- 

 fully coloured flower-like 

 gill-tuft with which the head 

 is crowned. Its separate 

 filaments are clothed with 

 vibrating hairs, which create 

 currents bringing food-par- 

 ticles 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 effectuallybar 

 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 difier 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 IvlEDlClNAL 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 traveler 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. 



The Flat-worms embrace a large number of intestinal and other parasitic species, includ- 

 ing Tape-worms, Thread- r 

 woRMS, Liver-flukes, and 

 others. Among the free-living 

 non-parasitic members of this 

 group, the so-called INDIA- 

 RUBBER-WORM is remarkable 

 for theextraordinaryelasticity 

 of its tissues. Black in hue, 

 it lives among rocks and sea- 

 weeds, and preys upon small 

 fishes and other organisms. 

 These, being seized b)^ the 

 suctorial mouth, are unable to 

 effect their escape, the worm's 

 body being capable of stretch- 

 ing out to a length of 20 feet 

 or more, and "playing" the 

 captured victim like a living 

 elastic fishing-line until its 

 struggles arc exhausted. 



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SEA-MICE 



PVorms^ ivitli remarkably iridescent hairs^ ivhich burrow in the sand 



