148 



TEREBELLA. 



principal tube. The creature that inhabits this 

 dwelling goes by the name of Terebella. Its 

 empty tubes are sometimes torn away from their 

 attachments by the power of the waves, and in 

 this case are thrown upon the sea-shore together 

 with the algse, shells, and other debris that mark 

 the line beyond which the proud waves can no 

 further go. Generally, however, they are fixed 

 with such firmness, that to procure an entire 

 specimen is a matter of some difiiculty. There is 

 no connexion between the tube and its inhabi- 

 tant, who seems on occasion to be able to take 

 little journeys among the rocks, and even to 

 swim on the surface of the water by spreading 

 its numerous tentacles abroad ^ the molluscs 

 spread their foot. Sometimes the terebella be- 

 comes ambitious, and instead of contenting him- 

 self with sand and tiny stones, affixes a stone of 

 some size to his tube. One that I possessed for 

 some time had fastened the centre of its tube to 

 a pebble more than an inch in length, and very 

 nearly the same in width. 



The reader will not fail to remark the analogy 

 between the tube-inhabiting annelid and the 

 iarva3 of the common caddis, or stone-fly of 

 anglers, which build tubes in a very similar 

 manner, pressing into the service all sorts of 



