56 POPULAR CONCHOLOGY. 



are supposed to be filled with fleshy filaments 

 from the mantle. The upper end of the tube, 

 which is rarely obtained perfect, is more or less 

 attenuated, and terminating in smooth undula- 

 tions, is reflected at the margins. This reflected 

 extremity is left entire at certain periods of 

 growth, and the tube is recommenced according 

 to the necessities of the animal. Some speci- 

 mens have been found with four or five of these 

 entire reflections."* 



7. Clavagella. — Shell, valves very small, 

 the one being placed on the ex- 

 terior, the other in the interior 

 of the tube, which is narrow and 

 open at one end, club-shaped and 

 spiny at the other. Animal un- 

 known. — 2 species recent, and 5 fossil. 



There are very few recent specimens of this 

 shell to be met with in cabinets : some have 

 been brought from the Australian and Polyne- 

 sian islands, and one living individual from the 

 bay of Guayaquil. It perforates stones, corals, 

 and even other shells. 



* Reeve's Con. Sys. 



