148 UNIVALVES. — SABELLA. 



basis of these animals is covered with various fragments 

 and particles of different marine and vegetable productions. 



The S. vegetabilis and S. arundinacea are covered with 

 fragments of twigs, the bark of stems or reeds, and bro- 

 ken pieces of tellina cornea. The S. ammoniata is coated 

 with fragments of the cornu-ammonis. 



The covering of the S. Indica is composed of capillary 

 sub-cylindrical agglutinated crystals of quartz; and that of 

 the S. clavata of various sized stones. 



Some of the species, as the S. scruposa, S. chrysodon, &c. 

 are detached; whereas theS. scabra is affixed by the base. 



The S. alveolata has numerous parallel tubes, communi- 

 cating by an aperture, forming in the mass the appearance 

 of honey-combs. It is an inhabitant of the European 

 coasts, and covers the rocks for a considerable space, and 

 is easily broken under the feet. The tubes are straightish, 

 and from two to three inches long. The S. rectangula is 

 one of the largest of the genus, and often measures nine 

 inches in length. 



There are no less than fourteen or fifteen species which 

 inhabit rivers and fresh waters ; and most of them are from 

 the waters of Thuringia and Belgium, where they are af- 

 fixed to stones, &c. The other species are from the Indian, 

 American, Northern, and European seas. 



SA^BELLX—SabeUa. 



Family 1. — Composed of grains of sand, stones, or shells. 



Scruposa — White sandy. Nigra — Black. 



ScahrsL— Rough. Stagnalis — River. 



Alveolata — Honeycomb. Conica — Conic. 



Chrysodon — Pebble. Uncinata — Hooked. 



Belgica — Tubular. Sabulosa — Gravel. 



Rectangula — Rectangular. Ammoniata — Ammonites. 



Capensis — Cape. Helicina — Helix. 



