ANNULATA. 



33 



Roget* gives an interesting account of the 

 manner in which these little creatures form 

 their tubes: — " If taken out and placed in 

 water upon sand, its actions may be observed. 

 It immediately drags towards its head frag- 

 ments of shells, and larger particles of sand, 

 where they are cemented together by the glu- 

 tinous matter which exudes from that part of 

 the surface. It has soon formed a kind of 

 collar, which it lengthens at every part of the 

 circumference. Having formed a tube of half 

 an inch or an inch in length, it proceeds to 

 burrow, and as it proceeds avails itself of the 

 materials, till the whole tube is completed. 

 The Terebella then turns itself in its tube, 

 so that the head is next to the surface, ready to 

 receive the water which brings its 

 food. In summer the whole task is 

 completed in four or five hours, but 

 in cold weather the progress is much 

 slower." 



7. Amphitrite. 

 — ■ Tube cylindrical, M^^^^n^ 

 membranous or co- ^^llll 



* Bridgewater Treatise. 

 D 



