292 POTAMIDIN.E. 



Ex. T. fiiscum, Chemnitz, }3l. 31, fig. 1. Operculum, 

 T. fuscum, fig. 1, a. Shell, T. fuscum, fig. 1, h. 



T.fuscum inhabits the salt-marshes and swampy tracks 

 near the mouths of rivers in the East Indian islands, 

 and their pointed spires may be seen sticking out of the 

 soft mud in incredible numbers ; they are so abundant 

 near Calcutta as to be used for burning into lime, being 

 exposed in heaps to the sun to kill the animals ; in 

 Borneo they are eaten by the natives in the same manner 

 as Pyraziis. 



Species of Telescojnum. 

 fuscum, Chem. laeve, Quoij and Gaim. 



Genus CERITHIDEA, Swainson. 



Eye -pedicels very long and thick, connate with the 

 tentacles nearly to their tips. 



Shell turreted, many-whorled ; apex of spire more or 

 less decollated, whorls longitudinally ribbed ; aperture 

 rounded, slightly emarginate anteriorly ; outer lip ex- 

 panded, with a dilated, thickened margin. 



U.v. C. Charbonnieri, Petit, pi. 31, fig. 2. Opercu- 

 lum, C. decollata, Linnceus, fig. 2, a. Shell, C. obtusa, 

 Lamarck, fig. 2, b. 



The Cerithidece are amphibious, crawling on the stones 

 and leaves in the neighbourhood of brackish water in 

 mangrove-swamps, and at the mouths of rivers ; during 

 the dry season they close the mouth of the shell with 

 the operculum, and hang, suspended by glutinous threads, 

 to small branches and mangrove roots. 



