112 The Official Guide to the 
crimson dye, which may be obtained by pressing on 
the operculum. The “ Helmet Shells” (Casszs) are 
well-known ornamental shells, and are much used 
in the manufacture of cameos. C. éesse/ata is a very 
pretty example. There are also some _ beautiful 
examples of the “Harp Shells” (Harfa); and of 
the Olives, known as “Rice Shell,” a good series © 
of which, as well as of the Cones, will be found in 
the Taylor collection; of these latter there are many — 
from which the epidermis has not been removed, as 
well as others polished and showing the most lovely 
and intricate markings. ‘The Volutes are also finely- 
marked shells, one known as V. musica, is so called 
from its having lines similar to the musical staff upon 
its shell. 
The Cowries (Cypra) are waite ornaments, 
conspicuous for the beauty of their markings and 
for their high polish, the shell being always covered 
by the two lobes of the mantle; they inhabit nearly 
all the warm seas of the world, but are most abun-- 
dant in the Pacific. C. moneta, the Money Cowry, 
is used as a medium of exchange; in British India 
about 4,000 are said to pass for a shilling. 
The ‘Weavers Shuttle” is the trivial name of 
Ovulum volva (and some of the vernacular names of 
shells appear to be very trivial) ; 1t has the aperture of 
the shell drawn out into a long canal at’each end. It 
is a West Indian species and feeds on the coral 
animal. The ‘‘Wentletrap,” or as it is sometimes 
called, the Ladder Shell, belongs to the large genus 
Scalaria, most of which are tropical species; S. pretiosa 
is a typical and beautiful example, pure white and 
lustrous ; the animal is said to exude a purple fluid. 
A singular form, known as Sz/iguaria, in which the 
tube is at first spiral and afterwards irregular, has 
the additional interest of having been brought from 
