ACME. 187 



and Alderney, and it has been found in districts 

 where there is no chalk. 



This mollusc is inactive and very timid, retreating 

 within its shell upon the slightest touch. It is a 

 vegetable feeder. In winter, and often during very 

 dry weather in summer, it buries itself in the ground, 

 removing the earth with its strong snout, which it also 

 uses as a hold-fast by which to draw itself upwards 

 when climbing. Its mode of progression is very 

 curious ; the sides of its cloven foot are alternately 

 moved forwards, each in its turn retaining its hold 

 while the other advances. 



GENUS II.— ACME* HARTMANN. 



Body elongated ; tentacles slender, without bulbs ; foot short, 

 narrow. 



Shell cylindrical, elongated ; mouth oval ; operculum horny. 



Acme LiNEA'TA.t Draparnaud. Pl. IX. 



Body milk-white, with minute brown specks ; snout narrow, 

 indistinctly wrinkled transversely ; tentacles diverging, tapering, 

 faintly wrinkled, transparent, whitish, with a row ot black specks 

 round the base ; foot rounded in front, ending in a slender tail. 



Shell cylindrical, tapering, thin, semitransparent, glossy, 

 yellowish-brown, sometimes dark brown, with strongish curved 

 transverse striae which are placed somewhat wide apart, and 

 sometimes with a few very faint spiral lines, which are only 

 visible by the aid of a lens; periphery rounded; epidermis 

 moderately thick; whorls 6-7, somewhat compressed, very 

 gradually enlarging ; spire bluntly rounded at the apex ; suture 

 well defined, but shallow ; mouth somewhat pyriform ; outer lip 



* A point. t Marked with lines. 



