a large horny sponge, of the order Keratosa, measuring up to 20 cm and longer, whose skeleton resembles elastic porous felt. The bath sponge is used for washing and for medical and industrial purposes. The most valuable bath sponges are of the genera Euspongia and Hippospongia. Sponge fishing is well developed in the Mediterranean and Red seas, off Madagascar, Australia, the Philippines, and Japan, and in the Gulf of Mexico and the Caribbean Sea.