84 GENERA OF SHELLS. 



TRITON. Shell oval or oblong, channelled 

 at base ; varices alternate, rare or subsolitary, 

 never forming a longitudinal series. Aperture 

 oblong. Operculum. 



Sometimes the triton has only one varix, viz. on the 

 right lip, which is never wanting. The varices are 

 generally smooth, never spinous. 



T. variegatum,nodifernm, australe, lampas, scrobiculator, 

 Spengleri, corrugatum, succinctum, pileare, lotorium, femo- 

 rale, pyrum, cynocephalum, tripus, eanaliferurn, retusum, 

 clavator, tuberosum, vespaceum, chlorostornum, anus, cla- 

 thratum, subdistortum, cancellatum, maculosum, clandes- 

 tinum, rubecola, cutaceum, dolarium, tranquebaricum, 

 undosum. 



ALATA. 



Shell with a more or Jess elongated canal at the base of the 

 aperture, the right lip of lohich changes its farm with age, 

 and has a sinus at the lower part. 



ROSTELLARIA. Shell fusiform or subturret- 

 ed, terminated inferiorly in a canal, with a 

 pointed beak. Lip entire or dentated, more 

 or less dilated by age, with a sinus contiguous 

 to the canal. 



The right lip of these shells rests, at the upper part, 

 against the elongated spire, and sometimes runs along 

 it : the sinus at the lower part of the same lip is quite 

 contiguous to the canal, which is not the case either 

 with pterocera or strombus. 



R. curvirostris, recticornis, pes pelicani, macroptera, co- 

 lumbata, fissurella. 



