ZOOLOGY. 265 



35. Tei'cdo. Ship-Worm, or Piercer, Inhabitant a Terre- 

 bellu, or Ascida. 



Shell tubular, tapering, slender, curved, one extremity closed 

 by two hemispherical, and the other, by two. lanceolate 

 valves. Plate 5, fig. 35. 



Though this genus is described as possessing valves, they 

 are not of the nature of those of the Multivalve genera, the 

 valves being rather parts of the animal than of the shell ; this 

 genus is extremely injurious to shipping, as they readily 

 penetrate the hardest oak, as likewise [josts or piles, that are 

 emersed in water ; they are confined to the ocean. 



36. Sabella. Concrete-Shell. Inhabitant various, as 



Nerics, Amphitrite^ S)C. 



Shell or case tubular, composed of particles of sand, broken 

 shells, and calcareous matter, cemented by a glutinous 

 exudation. Plate 5, fig. 36. 



It is not at present determined by (he most able concho- 

 logists, whether this genus has a claim to its present situation 

 among Testaceous shells, but as no better or more natural 

 station has been assigned to <hcm, we leave them as previ.« 

 ousiy arranged. They are found in the sea, and also in fresh 

 •water ditches, sometimes affixed to rocks and shells, and 

 at others, buried in the mud or sand. 



