MOLLUSKS. 327 
ily, called the Royal Staircase Wentletrap. This is found 
in the Chinese and Indian Seas. It is so costly—a fine 
specimen commanding, even now, four or five pounds 
sterling—that the specific name attached to it is pretiosa, 
precious. In the same figure is a specimen from the very 
extensive Cone family. In Fig. 258 the large shell is that 
of a Whelk, belonging to a family which, from the shape 
of the shells, is called Buccinide, from buccinum, a trum- 
pet. The famous Tyrian purple was obtained from one 
of this family. In the same figure is the little Cowry, 
which is a current coin among the natives of Bengal, 
Siam, and many parts of Africa. In Bengal, 3200 of 
these shells are reckoned equal to a rupee, or about two 
shillings of English money. In 1849 about three hund- 
red tons of them were imported into Liverpool, designed 
to be used in the African trade. One of the most beautiful 
of the shells which are armed with spines is the Thorny 
Woodcock, Fig. 259, sometimes called Venus’ Comb. 
Fig. 259.—Thorny Woodcock. 
