Gasterofoda.- 



-MOLLUSCA.- 



-Olivid.e. 



327 



slenderness and gi-aceful curvature. Tlie surface of 

 the shell is usually invested with an epidermis, often 

 soft and hairy, sometimes shiny and membranous, less 

 frequently altogether wanting. It varies also consider- 

 ably in colour, and grows to the length of six inches 

 by three wide. The animal of the Whelk is very slow 

 in its movements. Though it generally resides on the 

 surface, it has the power of burrowing in the sand 

 when in search of its prey. This action is produced 

 by means of its foot, which it is able to distend to a 

 size nearly equal to that of the shell. It is eminently 

 carnivorous, and its proboscis — fig. 214— enables it to 



Fig. 214. 



AAWM' 



I'luboscis and ticlli uf Biiccimini undaturii. 



drill holes through the hardest shell of any bivalve. It 

 is said to be very destructive to the common scallop 

 or clam {Pccten opercularis), by slily insinuating its 

 foot, and seizing upon the unwary inmate as it lies 

 with its valves unguardedly open. This is at least 

 mentioned by Montagu as the opinion of the fishermen 

 of the coast, who, he says, acting upon this supposition, 

 dredge for this Whelk, and either destroy the animal 

 or use it for bait. At Portpatrick it is called tlie Hen 

 Buckie, and is much used by the fishermen on that 

 coast as bait. It is caught for this purjiose in baskets 

 containing f)ieces of fish, which are let down in about 

 ten fathoms of water, and are drawn up daily to be 

 emptied of the shells which have crept into them to 

 feed upon the dead fish. " Each shell serves to bait 

 two hooks ; so that reckoning the number of hooks 

 used by all the boats at four thousand five hundred, 

 about two thousand two lumdred and fifty of these large 

 shell-fish must be destroyed every time the lines are 

 shot, and probably not fewer than seventy thousand every 

 year. Yet the supply, chiefly obtained from a space of 

 no great extent, seems to be even more abundant than 

 ever." — ( Wilson.) The Whelk is also used as food by 

 man. Thousands are exposed in the fish-shops and 

 stalls in the metropolis ; they are simply boiled and 

 eaten with a little vinegar and pepper — " a poor man's 

 delicacy, but by no means a wholesome morsel," says 

 Professor Forbes. " A repast, sufficiently wholesome, 

 and certainly not destitute of relish," says Dr. Johnston. 



F.AMiLY— CANCELLARIIDiE. 



The shells of this family are generally rough, with 

 stria; or ribs, or have a cancellated surface. The spire 



is short ; the mouth ovate, channeled in front ; and the 

 columella, or pillar lip, is marked with several strong 

 oblique folds. No operculum has been observed ; and 

 though the animal has been seen in some of the species, 

 the proboscis and teeth have not been examined. The 

 character of the shells would lead us to believe that 

 they belong to the carnivorous group, but M. Deshayea 

 asserts that the Mediterranean species, Canceltaria can- 

 cellata, is a vegetable feeder. The CancellariiS are 

 marine shells, many of them of rather an elegant form, 

 and much sought after by collectors. The number of 

 recent species are about seventy, and their native 

 countries are the Mediterranean, West Indies, Western 

 Africa, India, China, and California. They have been 

 dredged in from seven to forty fathoms. 



Family— OLIVIDiE. 



The family of OLIVES {OUcidif) are distinguished 

 by the animals having a large elongate foot, with a 

 cross groove on each side, often inclosing a part of the 

 shell. The mantle is inclosed, the siphon rccnn-ed, 

 and the canal of the shell reduced to a notch. This 

 is rather a large family, and contains the True Olives, 

 ihe Ancillarice, and the Harp Shells. 



Genus Oliva. — The True Olives have a subcylindri- 

 cal, smooth, polished shell, with a deep channeled suture 

 round the whirls, and the columella plaited in front. 

 The large foot is raised up on each side, in order to 

 envelope the shell, and secretes the enameled, shining, 

 and brightly-coloured layer, which covers the outer 

 surface of the shell. The mantle has an elongated 

 appendage, situated behind, and lodged in the deep 

 channel of the sutures of the spire. This is a remark- 

 able character of the Olives. The species are numer- 

 ous, nearly one hundred and twenty recent forms 

 having been described. They are carnivorous and 

 voracious animals ; are active ; and can turn over whei 

 laid on their back. Near low water they may be seen 

 gliding about, or burying tliemselves in the mud as the 

 tide retires. They are subtroi)ical shells, and have been 

 found in America, Western Africa, India, China, and 

 the Pacific, from low water to twenty-five fathoms. As 

 these shells are much sought after by collectt rs, they 

 are often obtained by fishing for them by a line baited 

 with a piece of raw flesh. 



THE PANAMA OLIVE (0. pnrplitjrca), the largest 

 and one of the finest species, is a m.tive of the coasts of 

 South America. It is marked with numerous fine, 

 brown, angular, or zig-zag lines, upon a flesh-culonred 

 ground, and frequently attains to five or six inches in 

 length. 



Gknus Ancillaria.— The Ancillari», with a sub- 

 cylindrical polished shell, have the suture of the spire 

 covered with a smooth, shining, thinnish callosity, instead 

 of a groove or channel. The mantle is destitute of tlie 

 posterior, elongated appendage of the Olives. The shell 

 is more or less covered with a fine coat of enamel ; in 

 some species leaving a naked space on the whirls, but in 

 others covering the whole shell. This arises from the 

 fact, that the foot of the animal is much expanded on 

 both sides, and curling upwards and inwards during the 

 ordinary progression of the animal, folds itself on the 



