MARINE MOLLUSCA OP THE UNITED STATES. 63 



thin and fragile ; pillar lip flattened, and with a small superficial 

 fold. Epidermis whitish or reddish-brown, with numerous bands 

 of brown ; pillar white. 



Length 10, diam. 12.5 mill. 



Generally covered with a calcareous incrustation ; underneath 

 zoned or frequently entirely white or flesh color. 



Coralline, on stones, dredged in 14 to 40 fathoms. 



Massachusetts northwards (Eur.). 



Family PYRAMIDELLID^E. 



The animal, in this family, is provided with broad, ear-shaped 

 tentacles which are often connate, with eyes behind them at their 

 bases; proboscis retractile; foot truncated in front; the tongue 

 unarmed. 



Synopsis of Genera. 



Shell subulate, tnrreted, many-whorled, smooth; spire pointed, nucleus 

 sinistral ; aperture semi-oval, entire, rounded anteriorly ; columella 

 straight, plicated ; outer lip acute. OBELISCUS, Humphrey. 



Shell slender, elongated, many-whorled, longitudinally ribbed; apex of 

 spire with a persistent, embryonic, sinistral nucleus ; aperture oblong or 

 subquadrate, peristome incomplete ; columella straight, simple, edentujate 

 and without a plait. TURBONILLA, Risso. 



Shell turreted, subulate or ovate, smooth or transversely striated ; apex of 

 spire sinistral ; aperture ovate, peristome not continuous ; columellar lip 

 with a single tooth-like fold. ODOSTOMIA, Fleming. 



Shell turreted, many-whorled, whorls smooth or spirally striated ; aperture 

 oval or rounded ; inner lip simple, without plaits or teeth, base often per- 

 forated. ACLIS, Loven. 



Shell elongated, imperforate, many-whorled, transversely striated ; aperture 

 small, ovate, entire in front ; columellar lip smooth or obscurely plaited. 



MENESTHO, Moller. 



Shell elongated, white, smooth, polished ; spire produced, many-whorled, 

 frequently with an interrupted varix on one side, apex acute ; aperture 

 oval, pointed behind ; inner lip reflected over the pillar ; axis imperforated ; 

 outer lip thickened internally. EULIMA, Risso. 



Shell subulate or subglobose, thin, pellucid, smooth, polished, many- 

 whorled ; apex of spire produced and styliform, with a sinistral nucleus ; 

 aperture sub-ovate, pointed behind, rounded and entire in front ; inner lip 

 smooth, arcuated ; outer lip thin, simple. STYLIFER, Broderip. 



