188 POPULAR HISTORY OF THE AQUARIUM. 



structure. It presents a beautiful double fan of gills, at 

 the end of its projected tube. It is rather a large AYorm, 

 beset with the usual bundles of satiny bristles, golden 

 tinted. The fans are broadly plumose and spirally curved, 

 forming a kind of shallow funnel, white and brown banded. 

 Mr. Gosse has noticed, in another species, S. vesictdosa, a 

 power of reproducing mutilated parts, and even forming en- 

 tirely WQ'N fans. 



Sabella alveolata. 



Congregations of this Worm make parallel tubes of sand, 

 fitting into each other, and composing a mass resembhng 

 a honeycomb. Entire floors of caves are sometimes covered 

 with this structure. The species is commonly called the 

 '^ Honeycomb Wormy 



Terebella conchilega. — (Plate I. fig. 2, 3.) 

 In turning over loose stones and gravel on a sandy shore 

 at low-water, you may find very brittle tubes composed of 

 minute pebbles, grains of sand, and small shells, neatly 

 fitted and cemented together. They are the work of a 

 marine mason, who has built them for his own occupation. 

 The Terebella is a worm, which, instead of the fan-Uke 



