BY E. M. JOHNSTON, F.L.S. 



95 



Sub-Genus Euchelus. Phil. 



Shell conoidal, turbinate umbilicated '; whorls rounded, with 



granulated revolving ribs ; columella lamellarly produced 



into a central- tooth ; outer lip thickened and crenulate 



within ; opercular whorls rather few, rapidly increasing. 



Sub-Genus Clancuxtts. Montfort. 

 Shell conoidal or turbinated, not umbilicated ; whorls mostly 

 granulous ; aperture contracted ; columella spirally 

 twisted, forming a false umbilicus, plicated throughout 

 and terminating in a multi-dentate varix ; outer lip 

 dentate within, with sometimes a larger superior tooth. 



Sub-Genus Diloma. Philippi. 

 Shell conoidal, smooth, not umbilicated; whorls rather few, 

 convex ; aperture sub-rotund ; columella lip excavated 

 in the middle and expanded over the umbilicus region, 

 produced laterally to join the outer lip ; outer lip thin, 

 unarmed. 



Genus Margarita. Leach. ( — ) 

 Shell thin, globular, conical, umbilicated ; whorls rounded, 

 smooth ; aperture rounded, pearly ; lip sharp, smooth. 

 Dist, — Japan, California, Australasia. 



(xlvi.) Family Stomatellid^:. 

 Genus Stomatella Lam. (389.) 

 Shell ear-shaped, regular ; spire small ; aperture oblong, very 

 large and oblique, nacreous ; lip thin, even edged ; 

 operculum circular, horny, multispiral. Dist. — On reefs 

 and under stones at low water. 



Genus Stomatia. Helbing. (390.) 



Shell like Haliotis, but without perforations, their -place being 

 occupied by a simple furrow ; surface rugose, smooth or 

 spirally ridged ; spire small, prominent ; aperture large, 

 oblong; outer magin irregular. Dist. — Java, Philippines, 

 Torres Straits, Pacific, Australasia. 



Sub-Genus Gena. Gray, 

 knell sub-spiral, oblong, auriform, depressed, smooth or striated ; 

 spire flattened, nearly obsolete ; aperture very large ; 

 no operculum. 



(xlvii.) Family Pleubotom:ariid^;. 

 obeli more or less comically elevated, turreted or trochiform, 

 with a marginal slit in the upper part of the outer lip, 

 or a row of perforations in the upper part of the 

 whorl ; aperture often pearly within. 



