84 Mr. Swainson on Achatinella. 



World, which (although I have not the book at this moment 

 before me) accurately represent my A. pica. In this, as well 

 as in all the other species, the thick and abruptly truncated 

 base of the pillar gives it the appearance of an obtuse tooth, 

 covered with a white enamel. The extreme margin of the outer 

 lip is acute, but it is internally bordered by a thickened rim. 

 These characters, in all the species I have yet seen, are 

 strongly developed, and render this group one of the most con- 

 spicuous in the family of Helecina. 



1. — A. pica. 



A. testd trochi/brmi, nigra ; apice columellceque hast albis. 

 Sliell trochiform, black ; apex and base of the pillar white. 

 Monodonta, semi-nifi^ra Lam.? 



Shell xV^^ ^^ ^" ^"^^ l^"g» body whorl convex, spite conic ; 

 the three upper whorls white or fulvous, without any convexity, 

 and forming a conic point. Suture thickened, and margined by 

 a sulcated groove : a character that runs through all the following 

 species, except A, acuta. Interior of the aperture, and base of 

 the pillar white ; the latter tinged with rose colour : margin of 

 the outer lip within, bordered with black. 



2. — A, perversa, 



A. testd sinistrorsci, sub trochiformi, fused faciis transversis nigricantibus 



lineisque longitudinalibus ; apice suturdque albis. 

 Shell reversed, sub-trochiform, fulvous brown, with darker transverse bands, 



and longitudinal lines; apex and suture white. 



Shell less trochiform, but somewhat larger than the last. 

 The terminal whorls of the spire are likewise formed in the same 

 manner ; these, together with the suture, the pillar, and the 

 aperture, are pure white. The rest of the shell is a drab coloured 

 brown, variegated by transverse blackish bands and lines ; and 

 sometimes by others, in a waved direction, near the suture. 

 The spiral line, which follows the suture, and the tip of the 

 shell, both of a pure white, renders this a very elegant species. 



3. — A. acuta, 



A. testd ovalo-ohlongd, castaned, fascid marginnli fulvd ; spird longiusculd, 



apice acuto, nigro. 

 Shell ovate-oblong, chestnut, with a marginal fulvous band ; spire somewhat 

 lengthened, acute, the tip black. 



Shell somewhat pyriform 5 the spire being poiuted, and con- 



