CONCHOLOGY. 35 



terminating posteriorly in an oval, sub-compressed club, rough- 

 ened by spiniforra tubes. Inhabits the Indian seas. One species. 

 Clavagella aperta. 



3. Genus Fistulana. PI. VI. 

 Animal. Provided with two protuberant calcareous tubes, cover- 

 ing parts of its body at the open end of the tube, each of which 

 is terminated with from five to eight cup-shaped calcareous, or 

 corneous appendages. It inhabits the sand, and perforates wood, 

 stones, and sometimes shells. 



Shell. Lamarck asserts that the tube and shell of this genus are 

 quite distinct. They have the shell free and detached within the 

 sheath, and neither of the valves fixed into the partition of the 

 tube, which is most generally testaceous, closed, and retort-shaped 

 at the posterior extremity. Inhabits the Indian seas. Four 

 species. 



Fistulana clava. Fistulana gregata. 



F. corniformis. F. lagenula. 



4. Genus Septaria. PI. VI. 

 Animal. Unknown. 



Shell. A very long testaceous tube, gradually attenuated to its 

 upper end, and divided internally by vaulted divisions seldom 

 complete, the extremity of which is terminated by two slender 

 tubes without interior partitions. Specimens of this genus have 

 been found five feet long. Found in sand on the shores of the 

 Indian sea. Two species. 



Septaria arenaria. Septaria maculata. 



5. Genus Teredina. PI. VI. 

 A fossil genus ; consisting of a testaceous cylindrical sheath, 

 the posterior extremity closed, and exhibiting the two valves of 

 the shell it encloses ; the anterior end open. Two fossil species. 



6. Genus Teredo. PI. VI. 

 Animal. Body very much elongated, vermiform : mantle very 

 fine, tubular, opening only at front and below for the issue of a 

 teat-shaped foot ; mouth small ; very short, distinct tubes ; the in- 



