158 SYSTEMATIC ARRANGEMENT 



Fig. 84. — Teeth of Elenchus (Australia). 



29. Bankiva. 



Shell turrited, porcellaneous, smooth, polished ; inner coat iri- 

 descent ; axis imperforated ; aperture ovate, longer than wide ; pillar- 

 lip twisted, truncated in front ; outer lip acute ; throat porcella- 

 neous. Operculum ? Animal ? 



1. B. varians, Adams, Gen. Moll. 425. t. 48. f. 6. 



B. Operculum ovate, few-whorled. Shell subglobose, solid (p. 147). 

 30. Aradasia. 



Shell top-shaped ; whorls rounded, granulately ridged ; axis per- 

 forated, sometimes masked ; mouth ovate ; pillar with a small tooth 

 in front ; outer lip thick, hlunt, internally crenated ; throat more or 

 less pearly. Operculum ovate, suborbicular, of few rapidly enlarging 

 whorls ; lateral filaments (4 * 4) elongate. 



1. A. canaliculata. Trochus c, Quoy, Voy. Astrol. t. 64. f. 21, 23. 



2. A. denigrata, Adams, Gen. Moll. t. 47. f. 6 a, operculum. 



31. Otavia appears chiefly to differ in the outer lip having a 

 distinct, thickened, marginal varix. The animal and operculum are 

 unknown. 



Fam. VI. STOMATELLIDiE. 



Foot large, fleshy, developed posteriorly. Shell more or less ear- 

 shaped, of a few rapidly enlarging whorls ; aperture open, expanded. 

 Frontal lobes between the tentacula two, distinct, lobed. Mantle 

 and shell entire ; sides without filaments. Gill single, lateral. Oper- 

 culum horny, whorls many, gradually enlarging ; sometimes wanting. 



a. Operculum distinct. Animal retractile into shell. 



1. Stomatella. 



Slid] suborbicular, depressed, spirally grooved ; spire conic ; 

 whorls rounded ; aperture wider than long. Animal spiral, retractile 



