Cowries

Cowries, a group of Gastropoda (q.v.) belonging to the family Cypraeidae, and the genus Cypraea. They are carnivorous in habit, and have an oval shell; the mantle extends back as two lobes, and as these deposit shell, the spire is concealed in the adult by a covering of smooth, polished, porcellanous material. The lip becomes much thickened and the mouth contracted when the animal becomes adult; this gave rise to the old idea that the animal abandoned its shell and formed a new one at successive periods. There are about 150 species known, most of which come from tropical seas; only the small Triva europeae occurs on the English coasts; this species ranges from Norway to the Mediterranean, and is found fossil in the Crags. Many of the tropical species are larger, and others are well-known owing to their use as currency. Cypraea tigris is one of the largest and most handsome, and is frequently used for cameo cuttings. Cypraea princeps is one of the most valuable owing to its excessive rareness, as much as £40 having been paid for a single specimen. The species used for currency are smaller and very abundant. The one most frequently employed is the Indian Arieia moneta; in India between 3,000 and 4,000 go to a rupee, while in Siam over 6,000 are worth a tical (ls. 6d.). In Africa their value is higher, and they are used in strings of 100 in each; a string is worth about 2-1/2d. The earliest Cowries occur in the Cretaceous rocks of India.