36 CONCHOLOGY. 



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 seas. Two species. 



Septaria areftaria. Septaria maculata. 



.5. Genus Teredlna. 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. PL 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- 

 ferior or respiratory one somewhat larger than the superior ; labial 

 appendages short and striated ; branchiae very long, narrow, 

 united, and prolonged throughout the extent of the tubular cavity 

 of the mantle ; only one large contractile muscle between the 

 valves ; at the point of junction of the mantle and tubes is a mus- 

 cular ring, in which is implanted a pair of corneo-calcareous ap- 

 pendages. 



Shell. Thick, solid, very short or annular, open before and 

 behind ; valves equal, equilateral, angular and trenchant before, 

 only touching each other by the opposite edges; no hinge; aeon. 

 ?iderable spoon-like cavity ; only one feeble muscular impression. 



