92 PROVISIONAL AID TO THE STUDY OF TASMANIAN MOLLUSCA. 



(xli.) Family Liotiidjb. 



(Shell depressed, spiral, white ribbed, sometimes cancellate, or 

 nodulous ; aperture orbicular, rarely pearly within ; 

 operculum corneous inside ; outside with a calcareous 

 coat of pearl-like shelly particles, spirally arranged. 



Genus Liotia. Gray. (319-324) 



Shell turbinated or depressed, varicose, perforated or umbilicated 

 whorls ribbed or cancellated ; aperture rounded, pearly 

 within; peristome thick, callously margined. Dist. — 

 Tropical and sub-tropical. 



Genus Cylostbema. Marryat. (325-333.) 



Shell orbicular, depressed, widely umbilicated, spire short ; 

 whorls transversely striated or cancellated. ; aperture 

 round, not nacreous ; peristome continuous, simple. 

 Dist. — Japan, Philippines, West Indies, Australasia. 



(xlii.) Family EoTELLiDiE. 



Genus Rotella. Lam. (334.) 



Shell depressed, lenticular, the spire depressed, conical ; 

 aperture semi-orbicular ; outer lip sharp ; base with a 

 convex rounded umbilical callus. List. — India, China, 

 Japan, Philippines, Australasia. 



(xliii.) Family PHASiANELLiDiE. 



Genus Phasianella. Lam. (335-339.) 



Shell elongated, polished, richly coloured ; whorls convex ; 

 aperture oval, not pearly ; inner lip callous, outer thin ; 

 operculum shelly, callous outside, sub-spiral inside. 

 (Pheasant -shell.) Dist. — Large species, Australasia ; 

 small species, India, Philippines ; very small species, 

 West Indies, Mediterranean, Great Britain. 



(xliv.) Family Tubbinid^e. 

 Genus Turbo. Linn. (340-342.) 

 Shell spiral, turbinated, solid, nacreous inside ; whorls convex, 

 smooth, grooved or tuberculated; aperture large, rounded, 

 slightly produced in front ; operculum shelly and solid, 

 callous outside and smooth, or variously grooved and 

 mamillated, internally horny and pauci-spiral. Dist. — 

 World-wide ; rocks and weeds at low water, along the 

 shore. {Top-shell) 



