The Caniculated Pear-Shell, ([Pyrula caniculata].)
This shell is found in the Icy Sea, and on the coast of Canada, and attains the length of seven inches. The animal of the Pyrula is at present unknown. There is a kind of keel or ridge along the edge of the whorls, which is obliterated in very old specimens. There are as many as eight-and-twenty species of this shell.
Turbo marmoratus.Pleurotoma babylonia. Trochus imperialis.
The Babylonian Split-Mouth,
([Pleurotoma babylonia].)
The Babylonian Split-Mouth is found in the East Indies and the Molucca Islands, and is about three inches and a quarter in length. It is said that the animal of this shell, when in motion, has its foot separated as it were from its body by a long thick footstalk, which arises from the centre of the mantle, which is at this time turned back over the shell. This separation of the foot has the effect of causing the creature to tumble over frequently, from the great weight it has to support.
VEGETABLE FEEDERS, (Phytophagi.)
Those genera of the Trachelipods which live on vegetable substances have no projecting siphon, but possess a mouth furnished with jaws; they are in general land-shells, and consequently, the air which they breathe is conveyed directly to their branchiæ. Some of their tribes however, live in fresh water, either in running streams or in stagnant pools: among these, some breathe water and others air. These last are obliged frequently to come to the surface for the purpose of breathing,—others again inhabit salt water, and are unable to exist out of that element.