92 THE ELEMENTS 



and fourteen species have been ascer- 

 tained to be indigenous to Britain. 



Genus 33d -DE NTALIUM. Ani- 

 mal a Terebella ; shell univalve, tubu- 

 lar, straight or slightly curved, with 

 cavity undivided, and open at both 

 ends. Linn. Syst. 332. Plate 9th, 

 fig. 33d. 



Habitation. The shells of this ge- 

 nus are only found to inhabit the 

 ocean. They are solitary, and are to 

 be found immersed in the mud, in an 

 oblique or perpendicular position. — 

 And the shores are those which have 

 flat extended beaches, and on which 

 a quantity of soft mud is collected, 

 commonly known by the name of 

 sludge. This genus is unquestionably 

 simple, and very distinct and perfect. 

 Continental Testaceclogists have also 

 endeavoured to overturn this genus, 

 but without effect. It is defined with 

 too much precision and simplicity to 

 be altered. 



