GASTROPODS. 



377 



parts of the Northumberland coast are remarkable for their solidity. Thousands of 

 bushels of this mollusc are annually consumed in London alone, and as much as 

 12,000 has been realised in a year by the whelk-fishery off Whitstable. Whelks 

 are used as bait in the cod-fishery. The operculum of this species is roundly ovate, 

 formed of concentric layers, the nucleus being a little excentric. It is compara- 

 tively small, and of no use as a defensive door to the shell. On the coast of Kent 

 and Sussex a race exists, provided with two and sometimes three small opercula, 

 instead of one as usual. It is a peculiarity which apparently has become 

 permanent to some extent, but how it 

 originated is a matter of conjecture. The 

 whelk has a wide geographical range, 

 occurring all over the North Sea to the 

 Norwegian Coast, as far north as Iceland, 

 and on the east coast of the United States 

 from Cape Cod northwards. It is found 

 fossil in the Coralline Crag. Owing to 

 the variability in the shell, a considerable 

 number of so-called species of Buccinum 

 have been described; but the total of 

 recognisable forms does not probably 

 amount to more than about sixty or 

 seventy. These are mostly Arctic or 

 northern, but a few are known from 

 Japan. Volutharpa is scarcely separable 

 from Buccinum, but the shell is thinner, 

 and the aperture very large. On the con- 

 trary, the operculum is minute, that of F. 

 perry i from the Japanese seas a shell 

 about 2 inches long being only about -f^ 

 of an inch in diameter. Neobuccinum is 



the Antarctic representative of Buccinum ; the single known species occurring at 

 Kerguelen Island in the Southern Ocean. The operculum differs from that of 

 Buccinum in being somewhat spiral, instead of concentric, and the lingual dentition 

 is slightly different. Cominella, Cyllene, Tritonidea, Pisania, and Euthria are 

 genera referred to the family Buccinidce, on account of general similarity in the 

 animals, and especially of the radula. They comprise a considerable number of 

 species 'from tropical and temperate localities, but are not of sufficient interest to 

 be further mentioned. We may, however, call attention to the genus Euthria, as 

 a remarkable instance of wide geographical range. The typical species, E. cornea, 

 which is very common in the Mediterranean, has also been found on the coast of 

 the island of New Caledonia, eastward of Australia. The genus Phos contains a 

 small number of very beautiful species with highly ornamental cancellated sculpture. 

 On the other hand, the closely allied Eburna is remarkable for the smoothness 

 of the shell, and the spotted character of the colour-markings. 



All the members of the family of dog-whelks (Nassidce) are comparatively 

 small, none exceeding 2 inches in length. The animal frequently has the foot 



SECTION OF WHELK (nat. size). 



