GENUS PYRAMIDELLA, LAMARCK. 



THE PYRAMIDELLA. 



Testa turrita, conico-elongata, epidermide destituted. Apertura Integra, 

 semi-ovalis ; labro acuto. Columella basi producta, subperforatA ; plicis 

 tribus transversis. Operculum corneum. 



Shell turreted, conical, elongated, slightly striated, destitute 

 of epidermis. Aperture entire, semi-oval, widened at its base, 

 lip inferiorly sub-perforated, and with three transverse folds. 

 Operculum horny, thin, ovate, elongated, elements very fine, 

 and folds oblique. 



Animal having a head surmounted by broad, rather long 

 tentaculae, formed like a pointed horn, and open on the side. 

 The mouth situated in a flattened, wide, dilated, and quite 

 deeply two-lobed muzzle, separated from the foot by a groove. 

 The respiratory cavity open throughout the whole length of 

 the mantle, bearing on its right margin a long and narrow 

 branchia. The heart has a direction from right to left. The 

 rectum and uterus are attached to each other along the bran- 

 chiae, and terminate in an ear-shaped gutter, produced by the 

 margin of the mantle. The mucous follicles line the upper 

 wall of the cavity. The foot is round, without a marginal 

 furrow, passing down before in form of an ear-shaped shield, 

 and bearing posteriorly a membranous operculum, with laminae 

 destitute of a spire, which possesses one or two notches to slip 

 upon the folds of the columella. 

 Pyramidella. A 



