322 TOILERS IN THE SEA. 



the extreme end of each filament, that it is 

 -.gifted with the twofold power of acting on the 

 sucking and on the muscular principle. In addition 

 to the two important uses already assigned to these 

 tentacles, they constitute also the real agents of 

 locomotion. They are first outstretched by the 

 forcible ejection into them of the peritoneal fluid, 

 they are then fixed like so many slender cables 

 to a distant surface, and then, shortening in their 

 lengths, they haul forward the carcase of the worm." l 

 " The tubicolous Annelids, those modest re- 

 cluses, who as soon as they emerge from the egg 

 begin to construct for themselves a habitation, 

 from which they never again depart. This habi- 

 tation which is lengthened and widened according 

 to the increasing bulk of the proprietor, is a 

 tube, either calcareous or composed of a sub- 

 stance somewhat similar to leather, or wetted 

 parchment. It completely envelopes the worm, 

 which ascends and descends in the interior, without 

 the necessity of rolling back its body (fig. 64), for 

 its feet are constructed in such a manner that they 

 can move backwards or forwards with equal ease 

 and facility. These animals therefore pass their 

 lives in a position somewhat similar to that of 

 -a child in swaddling clothes. The tube, which is 



1 Lewes, " Seaside Studies," p. 72. 



