Tornatellidse, and Pyramidellidse. 457 



tentacular membrane, forming a sort of head- veil to a little be- 

 yond the foot ; it is long, flat, and terminates in two arcuated 

 lobes with a wide central indentation between them ; the mouth 

 is not quite at the extremity of the head. The tentacular veil 

 originating in the basal coalition of those organs is entire, and 

 diverges into two very short, flat, broad, bevelled, subtriangular 

 tentaculiform processes rounded on the tips, on each of which 

 there are about nine intense white subcircular minute flakes ; the 

 eyes are not on the triangular bases of the tentacula, but a little 

 posterior to their origin, imbedded in the skin of the anterior 

 base of the neck exactly central ; that is, it can scarcely be appre- 

 ciated if the inclination be external or internal. The foot is large, 

 moderately long, auricled in front, bevelled to a very fine edge, and 

 when in the full extension of march tapers to a point, when at 

 rest it is rounded ; it is flat, of thin texture, of a pale blue hya- 

 line colour suffused with opake snow-white matter ; it carries on 

 a simple scarcely raised operculigerous lobe, situate quite at the 

 middle, or at the junction of the pedicle of the foot with the 

 body, an oblong-oval light corneous operculum, with a depressed 

 point as a nucleus, from which oblique striae of increment pro- 

 ceed. The branchiae, buccal apparatus, and the organs of repro- 

 duction were not seen, as the shells could not be destroyed, and 

 it is probable that their minuteness would have caused an attempt 

 to detect them to end in failure. We are therefore in the dark 

 whether the tongue is spinous or unarmed, as is the long flat 

 lingual riband in the cylindrical recondite proboscis of the 

 Eulimce. 



There is no tooth on the columella of this species, as in most 

 of the preceding ones, excepting the C. diaphana ; but there are 

 sometimes within the aperture of the ultimate volution one or 

 two minute denticles, as in Conovulus deniiculatus, and we have 

 the C. acicula with a decided pillar fold ; these columellar ap- 

 pendages cannot at all be depended on from their instability and 

 variableness ; they may serve as a kind of mark to distinguish one 

 species from another conchologically, but even that index fails 

 when the species is sometimes with and sometimes without the 

 denticle. 



This is a rare animal on the Devon coasts, but we have taken 

 several at Exmouth in the coralline zone ; it is by no means shy, 

 marching with vivacity, and allowing a good examination. 



Chemnitzia spiralis. 



Melania, Turbinella, et Odostomia spiralis, auct. 



Animal occupying a spiral shell of four flat volutions. Mantle 

 even. The colour in all parts is hyaline white, delicately suffused 



