364 



MOLLUSCA. 



Fig. 177 



less coated with a vitreous covering or enamel-like glaze, probably secreted by the mantle. The columella is 

 uniformly curved, audit is believed that none of the species have hitherto been found in the New World."— 

 Broderip.] [The Me!o, Broderip, resembles Cymba ; but its apex, instead of being shapeless and rude, takes a 

 well-fashioned and spirally-marked form. The colouring of the shell is also more elegant and vivid.] Others 

 ( Voliiia, Montf.) have the last whorl conoid, narrowing at the end opposed to the spire. The foot is less than in 

 the preceding genus. Their shells are often very remarkable for the beauty of the colours and patterns which are 

 painted on their surface. [There is reason to believe that the genera Cymba, Melo, and Voluta, are viviparous.] 

 Marginella, Lam., with the form of the Voluta, has the outer lip thickened and revolute. The sinus is slightly 

 marked. According to Adanson, the foot is also less, and has no operculum. The animal can partially cover its 

 shell by raising the lobes of its cloak. Tlie tentacula have the eyes upon the outer side at their base. M. de La- 

 marck distinguishes among them the Colombella, by the more numerous plaits 

 on the shell, and by a swelling of the middle of the outer lip. It appears 

 that there is no operculum. Mitra, Lam., has an oblong aperture with some 

 large folds on its columella, of which those next the spire are the largest. 

 Their spire is generally long and pointed. Several species are brilliantly 

 spotted with red upon a white ground. Their animal has a small foot, tenta- 

 cula of moderate length, with the eyes on the side one-third above the roots, 

 and a moderate siphon ; but it will often protrude a proboscis longer than the 

 shell. [The genus Conohelix, of Swainson, has a form more conical than the 

 typical Mitra; ; but its claim to be a good genus is denied by Sowerby.] Can- 

 cellaria, Lam. — The last whorl ventricose, and the aperture ample and round, 

 with a plate upon the columella : the spire is prominent, pointed, and the surface marked in general with cancel- 

 lated striae. [According to Sowerby, this genus is nearly allied to Purpura.] 



The Whelks (Buccinum, Linn.)* — 



Comprise all the shells furnished with an emargination, or short canal, bent to the left, and whose 



columella is not plaited. Bruguieres made four genera of them ; viz., Buccirmm, Purpura, Cassis, and 



Terebra ; which MM. de Lamarck and Montfort have still further subdivided. 

 Buccinum, Brug., comprises the emarginated shells without any canal, the general form being oval, as well as 



the aperture. The animals where known have no veil on the head, — a proboscis, two widely separate tentacula 



with the eyes on their outer bases, and a horny operculum. The siphon is prolonged beyond the shell. M. de 



Lamarck specially reserves the name Buccinum to such as have 

 the columella convex and naked, and the outer lip without 

 ribs or varix. Their foot is moderate in size ; their proboscis 

 long and thick, and their penis often excessively large. [The 

 shell of the remarkable genus named Trichotropis by Broderip 

 and Sowerby, is turbinated and keeled ; its aperture is wider 

 and rather longer than the spire ; the base entire : but imme- 

 diately below the obliquely truncated columella there is an in- 

 distinct canal. The shell is thin and delicate, covered with an 

 epidermis forming numerous sharp-pointed bristle-like pro' 

 cesses on the edges of the carina; outside the shell. The horny 

 operculum is much smaller than the aperture. The animal 

 resembles a Buccinum, dift'ering from it principally in having 

 only a very small fold of the mantle to line the nearly obsolete 

 canal of the shell. There is a British species (T. Iwrealis).] 

 i-i., 173— Buccinum iindatim Nussa has the Columella covcred by a plate more or less thick 



and broad, and the emargination deep, but without a canal. 



The animal resembles that of Buccinum, and there are shells intermediate between the two genera. Lamarck 



names Eburna those which join to a smooth shell, without plaits on the lip, a pillar that is deeply and widely 



uinbilicated. In general form their shell has a strong resemblance to the Olives. [There is no operculum.] The 



animal is unknown. The Ancillaria, Lam., has also a smooth shell, and at the base of 



the columella a striated appendage or varix, without an umbilicus, and without a 



groove round the spire. The animal, in such species as it has been observed in, is 



similar to that of Oliva, and has the foot even more developed. The same naturalist 



unites those which are ribbed in the direction of the whorls, under the generic name 



of Duliiim : the lower whorl is very large and ventricose. Montfort again subdivides 



Dolium into the Dolium proper, where the base of the columella is as it were twisted ; 



M\A \nio Perdix, where it is sharp. Their animal has a very large foot, dilated in 



front ; a proboscis longer than its shell ; slender tentacula ; eyes at their exterior 



side near the base ; the head without a veil, and the foot without an operculum. 



Harpa is easily recognized by the prominent ribs which cross the whorls, and of 



which the last forms a rim to the margin of the aperture. The shells are beautiful. The animal has a very large 



Forms the family Entomostuma of Bhii 



