“It is that _mollusca_ from the Indian Seas which is known to commerce by the French name _bouche de mer_ (a nice morsel from the sea). If I am not much mistaken, the celebrated Cuvier calls it _gasteropeda pulmonifera_. It is abundantly gathered in the coasts of the Pacific islands, and gathered especially for the Chinese market, where it commands a great price, perhaps as much as their much-talked-of edible birds’ nests, which are properly made up of the gelatinous matter picked up by a species of swallow from the body of these molluscae. They have no shell, no legs, nor any prominent part, except an _absorbing_ and an _excretory_, opposite organs; but, by their elastic wings, like caterpillars or worms, they creep in shallow waters, in which, when low, they can be seen by a kind of swallow, the sharp bill of which, inserted in the soft animal, draws a gummy and filamentous substance, which, by drying, can be wrought into the solid walls of their nest. Hence the name of _gasteropeda pulmonifera_. “This mollusca is oblong, and of different sizes, from three to eighteen inches in length; and I have seen a few that were not less than two feet long. They were nearly round, a little flattish on one side, which lies next to the bottom of the sea; and they are from one to eight inches thick. They crawl up into shallow water at particular seasons of the year, probably for the purpose of gendering, as we often find them in pairs. It is when the sun has the most power on the water, rendering it tepid, that they approach the shore; and they often go up into places so shallow that, on the tide’s receding, they are left dry, exposed to the beat of the sun. But they do not bring forth their young in shallow water, as we never see any of their progeny, and full-grown ones are always observed coming in from deep water. They feed principally on that class of zoophytes which produce the coral.