83 
EAST. 200L. GAL.] NATURAL HISTORY. 
They are divided into orders* according to the food 
they live upon* as Zoophagous and Phytophagous * (p. 
88 .) 
1. The Flesh-eating Gasteropodes* ( Zoophaga *) or those 
which prey almost exclusively on dead or living animal 
food* as they require the blood to be more perfectly aerated, 
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 pro¬ 
vided 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. 
They are unisexual* and the females are generally much 
larger* and have much more ventricose whorls to their 
shells than the males. The eggs of these animals are 
contained in coriaceous cases* each holding many eggs* 
of which only a few gradually enlarge and come to per¬ 
fection. The cases of Buccinum undatum , and Fusus 
despectus have been mistaken for the eggs of the oys¬ 
ter* and called oysterspat . 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. 
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 animal of 
