Wo 



rms 



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 usefnl function tlms performed by 

 worms in bringing up earth from consideralile depths and redepositing it upon the surface of 

 the ground has been fully demonstrated in one of ^Ir. 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 tliese 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 pro|)ortionate, may vary from that of a man's finger to that of 

 an ordinary sausage. 



The most numerically abundant and stvacturally varied representatives of the bristle- 

 bearing worms are inhabitants of the sea, and are divisible into two easily recognised 

 natural groups. In one (if 



these the animals resemble / . 



earth-worms in their ability . -^ , '. .;, '' 



to move about freely from 

 place to place. In the other 

 group they secrete and perma- 

 nently reside within a tubular 

 edifice, which may be cal- 

 careous and of shell-like hard- 

 ness, 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-«'ORM (held in high 

 repute for fishing-baits), and 

 a host of other allied species. 

 In all of these the develop- 

 ment of bristles and other 

 appendages is more jiro- 

 nounced than in the Earth- 

 worms. In another group, 

 known as the Nereids, the 

 elongate worm-like fiody is 

 more or less flattened in shape ; 

 unjointed leg-like appendages, 

 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 antennte-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-stractures. Some of the larger species attain a length of several feet, and are 

 especially noteworthy for the brilliantly iridescent tinthig of tlieir skins. The palm of beauty 

 with respect to its brilliant colouring must undoubtedly, however, lie 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 U- to 2 inches wide. The centre 

 of the back is covered in bv 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 



Plwtohii ir. Sia-ilh-Kcat, F-Z..S.] 



[J/:iford-on-Sca. 



TUBE-W0E3IS. 

 Some witli their floiver-Iike gill-tufts exp.indei!. 



