302 THE AQUARIAN NATURALIST. 



labours of this architect, and always receives a de- 

 cided preference. Some particles of this material are 

 certainly swallowed preparatory to their being incor- 

 porated with the edifice ; but, from the dimensions of 

 others, it is evident that they must be fixed in their 

 places by means of some kind of adhesive matter. 

 When closely examined, the whole structure evidently 

 consists of a very tough silk, covered with fragments 

 of shell. 



Specimens of this Terebella have survived nine 

 months in confinement. 



On some shores the Terebella conchilega is the 

 most abundant of all the larger Annelides, with the 

 exception of the Arenicola. They are most numerous 

 about midway between high and low water-mark, 

 where the sand is mixed with a large proportion of 

 stones. By the shifting of the sand in storms they 

 are often buried to a considerable depth, and at other 

 times have several inches of their tube exposed. In 

 the first case they speedily work up to the surface ; in 

 the other the exposed portion of the tube is soon 

 broken off by the waves, or crumbles from exposure 

 to the sun. Their tubes are very long, and the animal 

 remains towards the bottom, except when seeking for 

 food. Hence specimens are to be obtained only in 

 favourable situations, for it is almost impossible to 

 dig up the whole fabric. 



As soon as the Terebella is removed from its case, 

 it throws itself into spiral folds. If now it is placed 

 under water upon sand, it forthwith straightens the 

 body, and presently all the tentacula are seen in full 

 action. They are extended in every direction, often 



