These are amusing facts; the following, to the epicure at least, may be equally interesting. In some parts of England it is a prevalent and probably a correct opinion, that the shelled-snails contribute much to the fattening of their sheep. On the hill above Whitsand Bay in Cornwall, and in the south of Devonshire, the _Bùlimus acùtus_ and the _Hèlix virgàta_, which are found there in vast profusion, are considered to have this good effect; and it is indeed impossible that the sheep can browse on the short grass of the places just mentioned, without devouring a prodigious quantity of them, especially in the night, or after rain, when the Bùlimi and Hèlices ascend the stunted blades. "The sweetest mutton," says Borlase, "is reckoned to be that of the smallest sheep, which feed on the commons where the sands are scarce covered with the green sod, and the grass exceedingly short; such are the towens or sand hillocks in Piran Sand, Gwythien, Philac, and Senangreen, near the Land's End, and elsewhere in like situations. From these sands come forth snails of the turbinated kind, but of different species, and all sizes from the adult to the smallest just from the egg; these spread themselves over the plains early in the morning, and, whilst they are in quest of their own food among the dews, yield a most fattening nourishment to the sheep." (_Hist. of Cornwall_.) Among birds the shell-fish have many enemies. Several of the duck and gull tribes, as you might anticipate, derive at least a portion of their subsistence from them. The pied oyster-catcher receives its name from the circumstance of feeding on oysters and limpets, and its bill is so well adapted to the purpose of forcing asunder the valves of the one, and of raising the other from the rock, that "the Author of Nature," as Derham says, "seems to have framed it purely for that use." Several kinds of crows likewise prey upon shell-fish, and the manner in which they force the strong hold of their victims is very remarkable. A friend of Dr. Darwin's saw above a hundred crows on the northern coast of Ireland, at once, preying upon muscles. Each crow took a muscle up in the air twenty or forty yards high, and let it fall on the stones, and thus broke the shell. Many authorities might be adduced in corroboration of this statement. In Southern Africa so many of the Testàcea are consumed by these and other birds, as to have given rise to an opinion that the marine shells found buried in the distant plains, or in the sides of the mountains, have been carried there by their agency, and not, as generally supposed, by eruptions of the sea. Mr. Barrow, who is of this opinion, tells us, in confirmation of it, that "there is scarcely a sheltered cavern in the sides of the mountains that arise immediately from the sea, where living shell-fish may not be found any day of the year. Crows even, and vultures, as well as aquatic birds, detach the shell-fish from the rocks, and mount with them into the air: