310 MELANOPSINiE. 



Sub-gen. canthtdomus, Svvaiuson. 



Spire generally short, whorls coronated with spines, or marked 

 with longitudinal ribs, the last obtuse anteriorly. 



cariosa, Linn. Parreyssii, Miihlf. 



costata, Oliv. Theminckiana, Petit. 



Helena, Modeer. tigris, Feniss. 

 Kotschyi, V. d. Busch. 



Sub-gen. lykcea, H. and A. Adams. 



Shell ovately fusiform, whorls transversely sulcate ; inner 

 lip with a large, posterior callus; columella subtruucate ante- 

 riorly ; aperture canaliculated posteriorly. 



Dufourii, Graells. nodosa, Feniss. 



Genus FAUNUS, Montfort. 



Shell subulate ; spire elongated, many-whorled, whorls 

 smooth, covered with a dark-coloured epidermis ; aperture 

 widely emarginate in front j inner lip thickened, with a 

 callus posteriorly ; outer lip dilated, the margin sinuated 

 towards the hind part. 



Si/n. Pirena, Lam. Ebena, Schum. Pyrena, Mke. 

 Melanomona, Bowd. 



Ex. F. ater, Linnaiis, pi. 32, fig. 9. Operculum, F. 

 ater, fig. 9, a, 9, h. Shell, F. ater, fig. 9, c. 



The species of this genus, which differs from Melanopsis 

 in the length of the spire, and in the sinuated, broadly -ex- 

 panded outer lip, inhabit the beds of tropical rivers and 

 rivulets, where they may be seen crawling on the soft 

 mud at the bottom, feeding, apparently, on the decayed 

 vegetable matter. 



