NATURAL HISTORY* 
109 
GALLERY.] 
order contains the greater part of the Gasteropodous Mol- 
lusca which are furnished with large and distinct shells. 
They are divided into sections, according to the food they 
live upon and the position of their eyes. 
1. The Zoophagous Gasteropodes, or those which prey 
almost exclusively on dead or living animal food, have a 
syphon attached to the inner side of the front part of the 
mantle, to enable the water more freely to arrive at their 
respiratory organs. Their shells are always provided with 
a canal, placed in the front of the pillar which is formed to 
protect this syphon. They are furnished with a retractile 
proboscis, armed with teeth, which enables them to form 
round holes in bivalve and other shells, for the purpose of 
extracting the inhabitant; their operculum is always horny, 
and formed of irregular concentric plates. The eggs of 
these animals are contained in coriaceous cases, each hold¬ 
ing many eggs, of which only a few gradually enlarge and 
come to perfection. The cases of Buccinum undatum , and 
Fusus despectus have been mistaken for the eggs of the 
oyster, and called oyster spat. This error is the more re¬ 
markable, as oysters are ovoviviparous, the young being 
found in the branchiae of the parent in the month of July: 
the eggs of Purpura and other genera have, by a similar 
error, been described as a species of Tubularia. 
The species of these shells are extremely apt to vary 
according to the roughness or smoothness of the sea they 
live in, and the quantity and quality of their food ; thus, 
some of the common Whelks are thick and rugose, others 
very thin, even, and finely coloured. Rarely the whorls 
of these shells turn contrary to the common direction, 
from left to right, and sometimes, when the shell has been 
injured in its growth, the succeeding whorls are turned 
out of their usual course, and the shell becomes very 
much elongated or bent. (See p. 86, Cases 3 and 4.) 
The larger species are used as food by the natives of 
the sea-coast, and as bait by the fishermen. In Scotland 
the shell of the large Fusus despectus is used as a lamp. 
In India and China the different species of Turbinellus are 
used to contain the oil to anoint the priests. The ahimal of 
Purpura Lapillus yields a beautiful purple colour, which 
has been considered as the Tyrian dye of the ancients ; but 
there is little doubt that this colour was obtained from 
