Aviculidæ (PEARL MUSSELS or PEARL OYSTERS)

Lamellibranchs without siphons, with une qui valved, oblique shell, having a fine inner layer of mother-of-pearl. The anterior adductor muscle is small; the foot is small and secretes a by us. Meleagrina is the pearl-mu el especially, and inhabits the gulfs of the Indian Ocean and the Gulf of Mexico. IMG:content-0382.jpg:[blocks in formation] The most famous pearl-fishery is located on the n. shore of Ceylon. The oysters are taken in the spring by divers, in ten fathoms of water. The largest pearls approach two inches in length, but the best average the size of peas. Besides the loose pearls, which are formed around a foreign object, as grains of sand, dead oyster-eggs, etc., the pearly layer all over the inside of the shell has commercial value. Great Britain uses $500,000 worth each year, ab. 3,000 tons.