WORMS. 



155 



Those worms furnished with hair form the order seti- 

 gera or chetopoda, while the others are called asetigerous 

 or apoda. 



Among the setigerous worms are some that live in 

 tubes that they construct ; they are the tubicolae ; others, 

 that have no regular holes, are called wandering 

 worms. 



The tubicolate annelidans inhabit the strong tubes 

 that are often found covering rocks, stones, and other 

 submarine masses; among them the. most common is 

 the serpula ; their tubes are found in great 

 numbers on the shells of scallops, and if one of FIG. 88. 

 these shells, freshly taken from the sea, be im- 

 mersed in salt water, the creatures come out of 

 their tubes and spread out their gills like fan- 

 shaped crests, red or blue in color, and having 

 branches of exceeding delicacy. 



The lobworm, which is a type of the wander- 

 ing species, lives in the sand of rivers, and is 

 used as bait in fishing. 



Earthworms are the only annelides that are 

 not aquatic. They live in moist soils, feeding on 

 animal and vegetable debris; they sometimes 

 appear to render important service to agricul- 

 ture by breaking up and rendering porous soils 

 that are too compact because of a large pro- 

 portion of clay. Earthworms have no gills, 

 and respire through their skin ; they are thus 

 distinguished from the lobworms and tubico- 

 lidse, both of which have gills. They have very 

 short hairs on the ventral surface, but they 

 use these hairs in locomotion, arid must therefore be 

 classed as setigera. 



LOBWORM 

 (Areni- 

 col. pisca- 

 torum). 



