all power of description in the beauty of its colorings. The large Helmet- Shells^ of the genus 
Cassis, are extensively used in the manufacture of cameos. 
Genus BUCCINUM : Buccinum, includes several species, of which the Common Whelk, B. 
undatum, is the type ; this is extensively caught in dredges in Europe, as it is eaten, and is also 
used as fish-bait. It is well known to bore through the shells 
of other mollusca, and thus to suck out the vital parts. A 
curious illustration of this habit is furnished by Mr. Stephen- 
son, in describing the erection of the Light-house on the Bell 
Rock, off the Southwestern coast of England. On the first 
landing of the workmen there, the limpets, of a very large 
size, w^ere common, but were soon picked up for bait. As 
they disappeared, an effort was made to plant a colony of 
mussels, from beds at the mouth of the river Eden, of a 
1^ larger size than those which seemed natural to the rock. 
These larger mussels w^ere deemed likely to prove useful to 
the workmen, and might have been especially so to the light- 
jeepers, the future inhabitants of the rock, to whom that 
moUusk would have afforded a fresh meal as w^ell as a better 
bait than the limpet ; but the mussels were soon observed 
to open and die in great numbers. The reason of this was 
not readily discernible, but at length it was ascertained that 
the whelk had greatly increased, and proved a successful 
enemy to the mussel. It was repeatedly observed to perforate a small hole in the shell, and 
then to suck out the finer parts of the body of the mussel; the valves of course opened, and 
the remainder of the mollusk was washed away by the sea. The perforated hole was generally 
— such is the instinct of these little creatures — in, the thinnest part of the shell; it was per- 
fectly circular, but widened toward the outer side, and so perfectly smooth and regular as to 
have all the appearance of the most beautiful work of an expert artist. Several subsequent 
attempts were made to plant mussels in this place, but they were ail destroyed by the preda- 
ceous whelks. 
Another British species of Whelk, the B. lapillus, produces a purple dye, similar to that 
obtained by the ancients. Mr. W. Cole of Bristol, in 1684, thus described the process adopted 
in England for obtaining this color : " The shells being harder than most ot other kinds, are to 
)>e broken with a smart stroke with a hammer, on a plate of iron or firm piece of timber, with 
THE COMMON WHELK. 
