86 PROVISIONAL AID TO THE STUDY OF TASMANIAN MOLLUSCA.. 



Genus Etjximella. Forbes. 

 Sub-Genus Styloptygma. A. Adams. (233.) 

 elongated, pupiform, turriculate, solid, smooth or 

 slightly ribbed, polished; whorls inflated middle of 

 spire, numerous; apex sinistral; aperture sub-quad- 



Shell 



rangular. 



Dist.— Europe, Japan, Australasia. 



(xxxii.) Family Littoeinid^. 

 (Shell _ spiral, turbinate or globular ; peritreme entire; 

 interior not nacreous ; operculum corneous, spiral or 

 or pauci-spiraf:f 



Genus Littobina. Ferussac. (234-238.) 

 Shell turbinated, thick, pointed, few whorled ; aperture 

 rounded ; outer lip acute ; columella rather flattened, 

 imperforate, operculum, pauci-spiral. Dist.~ Universal 

 on sea shores. 



Genus Eisella. Gray. (239-241.) 



Shell depressed, trochiform, with flattened whorls and keeled 



periphery ; not umbilioated ; aperture rhomboidal ; 



marked with brown inside the margin ; operculum 



pauci-spiral, distinguished from Trocbus, which they 



resemble, by their non-nacreous interior. Dist. 



Australasia, sea shore. 



Genus Fossaeus. Philippi. (242-244.) 

 Shell minute, turbinate, perforate, sculptured ; inner lip thin • 

 aperture semi-lunate ; operculum not spiral. Dist.— 

 Almost world-wide ; among weed at low water. 



(xxxiii.) Family Planaxib^;. 

 Genus Alaba. H. and A. Adams. (245-247.) 

 Shell ovate, conical or elongated, sub-diaphanous; whorls plicate 

 or varicose ; apex su b-mamniillate ; aperture ovate, the 

 columella more or less truncate. Dist.— Japan, West 

 Indies, Australasia. 



Sub-Genus Diala. A. Adams, 

 Whorls not varicose, sometimes nodulate around the middle • 

 columella straightish, not truncated; labrum not 

 thickened. Dist,— Philippines, Japan, Australasia. 



(xxxiv.) Family Ceeithiid^e. 



Shell spiral, elongated, many whorled, frequently 

 a.-herture channeled 'in front, wif.h a. A>rr ^/.%^v«.^ 



varicose 



aperture channeled in front, with a less distinct posterior 

 canal ; lip generally expanded in the adult ; operculum, 

 horny, spiral. 



