US UNIVALVES. SABELLA. 



SABELLA.— Saeella. 



AnimaL^a Nereis, with a ringent mouth, and two thicker 

 tentacula behind the head: Shell tubular, composed of 

 particles of sand, broken shells, and vegetable substances, 

 united to a membrane by a glutinous cement. 



This very extraordinary genus contains no less than 

 twenty-five species. The membrane which composes 

 the basis in these animals, is covered with various frag- 

 ments and particles ofdifFerent marine productions; some 

 are covered with sand, others with minute fragments of 

 shells mixed with the sand; many are covered with parts 

 of shells only ; and one, the Sabella Vegetabilis, is covered 

 with fragments of twigs, the bark of stems, and broken 

 pieces of Tellina Cornea. The Sabella Ammoniata is 

 also composed of fragments of the Cornu-Ammonis. 



The Sabella Indica is composed of capillary sub-cylin- 

 drical agglutinated crystals of quartz, the Sabella Clava- 

 ta of various sized stones, and the Sabella Arundinacea of 

 fragments of the bark of reeds, placed on each other. 



Some of the species, as the Sabella Scruposa, Sabella 

 Chrysodon, &c. &c. are solitary, whereas the Sabella 

 Scabra is affixed by the base. 



The Sabella Alveolata has numerous parallel tubes, 

 communicating 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 

 Sabella Rectangula is one of the largest of the genus, and 

 often measures nine inches in length. 



