328 TROCHHXS:. 



tremity ; veil slight, and bilobed : tentacles marked with a 

 broad red-brown line down the middle : eyes dark-blue with 

 black pupils, placed on short, but stout, white stalks: foot very 

 large, truncated in front, and lobed or angulated at each cor- 

 ner, granulated at the sides, and pointed behind ; sole fringed ; 

 crest white and puckered : appendages 3 on each side, white, 

 shorter than the tentacles, but equally flexible. 



SHELL exceedingly dilated and rounded at the base, with a 

 slight incurvation towards the apex, moderately solid, opaque, 

 and scarcely glossy: sculpture, from six to eight concentric 

 ridges, and about as many smaller intermediate ones, on the 

 upper part of the last whorl, besides an equal number on the 

 lower part ; the next whorl has nearly the same number and 

 alternate disposition of ridges as are visible on the upper half 

 of the last whorl, the ridges on the succeeding whorls becoming 

 gradually fewer; the larger ridges, or some of them, are usually 

 granulated, and invariably those at the apex ; the whole sur- 

 face is covered with very minute and close-set oblique longi- 

 tudinal striae ; in younger specimens the periphery is encircled 

 by a stronger ridge, which gives a keeled or angulated appear- 

 ance to that part, and forms a kind of crest on the top of each 

 of the upper whorls : colour yellowish-white, with a faint 

 tinge of reddish-brown, and speckled with the latter colour 

 on all or most of the principal ridges, or else irregularly 

 marked lengthwise by blotches of the same hue ; the larger 

 ridges on the base are always prettily spotted : spire moderately 

 raised, and tapering somewhat abruptly to a fine point : whorls 

 10, rather flattened; the last considerably exceeds all the 

 others put together : suture slight, defined by a shallow furrow 

 or level space between the uppermost ridge of each whorl and 

 the lowest ridge of the preceding one : mouth obliquely trun- 

 cated, slightly effuse or spread out below, rounded without, 

 and angulated within : outer lip thin : inner lip white, and 

 reflected on the pillar, which is extremely thick and somewhat 

 curved, with occasionally an obscure tubercle near the base ; 

 behind the pillar is a slight depression, like a rudimentary 

 umbilicus : inside highly nacreous : operculum rather concave, 

 with a small cup-shaped pit in the centre, and having from 

 fifteen to eighteen volutions ; it is microscopically, but indis- 

 tinctly, striated in a radiating direction. L. 1-5. B. 1/5. 



Yar. 1. lactea. Milk-white and spotless. 



Yar. 2. conoidea. More regularly conical and solid, with 



