52 
NATURAL HISTORY. 
[EAST. ZOOL. 
and called oysterspat. This error is the more remarkable, 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 suc¬ 
ceeding whorls are turned out of their usual course, and the shell be¬ 
comes 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 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 various species, which were 
most common in the district; the true Tyrian dye was most probably 
derived from Murex trunculus. 
The family of Strombs( Stroheim:, Cases 1,2) are peculiar for having 
a very compressed foot, which only allows them to move from place to 
place by putting their foot across the line they wish to proceed, and then 
turning themselves over towards the places of their destination, and con¬ 
tinually repeating this progress ; they are active; their eyes are large, 
and placed on the end of a large thick elongated peduncle, having the 
slender tentacles arising out of the middle of the hinder sides, and the 
shell is peculiar for having a deep sinus placed on the side near the 
canal over the head of the animal, when it is expanded. These animals, 
when they arrive at their full size, expand the edge of the mantle in a 
remarkable degree, which causes the shell of the adult animal to be*very 
different from that of the young. This expansion only takes place once 
in their lives, and not at repeated and stated periods, as in the Murices, 
&c. Their operculum is narrow and claw-like, the apex being pro¬ 
duced beyond the point of its attachment, as it enlarges, by new layers 
below; they use it as a weapon of offer ce when they have turned them¬ 
selves on their back, and the tube of the syphon is always bent towards 
the right side. They live on dead flesh. The genus Terebellum 
V has-no operculum, and live in muddy places in deep water. Some 
of these have the sinus separated from the canal by a space, as the 
Strombi, which have the under lip simply expanded and entire; the 
Pteroceras, or spider-claw, which has this part divided into lobes, which 
sheath the appendages which are produced on the edge of the mantles 
when the animal arrives at its perfect state of developement. In others 
the sinus is confounded wfith or quite close to the canal, as in Fostel- 
laria , which has an expanded or toothed outer lip to the shell; and 
Terebellum, which has a simple one and a linear mouth. Seraphys is a 
fossil genus, which only differs from the latter in having the spire en¬ 
veloped by the outer whorls of the shell. 
All the other flesh-eating comb-gilled Gasteropodes have a broad ex¬ 
panded foot, by which they glide on and attach themselves to marine 
