This species of Pinna is especially abundant on the shores of Sicily, in the Gulf of Taranto, and in the Bay of Naples, particularly beyond the Cape of Posilipo. It always fills my mind with the greatest delight to recollect the manner of fishing for it, in which I have often taken a part at that spot in the commencement of spring. On the northern shore of the Isle of Nisida opposite Posilipo, is a most agreeable expanse of water, where the sea appears to be ever at rest. Here, amidst those vast and most beauteous submarine forests, with which the coast is decorated in every direction so as at once to charm the mind and refresh the eye, the Pinna grows spontaneously in large groups, and in calm water, when the shadows fall from the summit of the island, is clearly seen by persons in boats growing nearly upright and fixed in the sandy bottom at the depth of about thirty feet. There are divers, whose business it is to bring it up. But, since it cannot be loosened even by repeated blows, (for the sand firmly resists the attempts of the diver, being supported by its own weight and by the super-incumbent water,) in these circumstances he sits down at the bottom of the sea, brushes away with his fingers the earth which encompasses the shell, and then endeavors to pull it up by seizing it with both hands. If he is thus likely to be detained at the bottom for a longer time than he can hold his breath, he ascends to the surface, supports himself _upon corks_, which are in readiness for him, and, when he has sufficiently recovered himself by breathing, he again dives to the bottom to complete his task. The specimens of Pinna in the British Museum show not only the tuft, but also the pearls and the mother of pearl. Poli found in one specimen of the Pinna Nobilis no less than twenty pearls, of which he has given figures in his splendid work. Pliny (l. ix. c. 35.) mentions the practice of diving for the Pinna in the Mediterranean Sea in order to obtain pearls from it: and Athenæus (l. iii. p. 93 Casaub.) has preserved extracts from two historical writers, one of whom accompanied Alexander on his Indian expedition, and who informs us, that the Pinna was procured in the Indian seas, by diving and for the sake of the pearls. The Italians call the fibres _Lana Pesce_ or _Lana Penna_, i. e. _Fish Wool_, or _Pinna Wool_. It is not equally good in all places. When the bottom of the sea is sandy, the shell with its bunch of fibres may be easily extracted, and they are silky and of a fine color. But in rushy and muddy bottoms so fast do they stick as to be generally broken in drawing up, and are of a blackish color without gloss.