272 THE AQUARIAN NATURALIST. 



CHAPTER XXVIII. 



SERPULA AND SPIRORBIS. 



" And far beneath the tempest's path 



In coral grots defies the foe, 

 That never brake in heaviest wrath 

 The sabbath of the deep below." 



J. MONTGOMERY. 



NATURALISTS divide the Annelida into erratic and 

 sedentary. The former, as may be easily concluded, 

 have no permanent abode ; the latter occupy a fixed 

 habitation, sometimes of very durable materials and 

 solid construction. They are themselves its con- 

 structors, and many of them real architects of a very 

 ingenious kind. 



Among the tube-inhabiting or sedentary Annelides 

 we shall describe a few of those most frequently met 

 with upon our own shores, in order to illustrate their 

 habits and general economy, selecting more especially 

 such species as are best adapted to become residents 

 in the aquarium, either on account of the elegance of 

 their forms, or the interest attaching to their habits. 



Every one must have observed that stones, dead 

 shells, fragments of pottery, or any similar substances 

 that have been sunk for a length of time in the sea, 

 become covered over with irregularly-twisted cal- 



