AFRICAN PAPER SHELL SNAIL. A prettily formed snail of medium size, of somewhat flattened shape, with attractive brown markings on a horncolored background. One of the better ones, a good scavenger and one that won't attack aquatic plants. If you breed snails, include this one, for it is easy and quite useful. Every time you clean your pool you will find empty shells of this species, for it is comparatively short-lived.

   AUSTRALIAN RED SNAIL. One of the smaller species, with a conchshaped shell, bright orange-red. Very useful, of average hardiness, and reproduces in pool or aquarium without special conditions.

   JAPANESE SNAIL. Also called Great Japanese Snail, Trapdoor Snail. One of the largest and one of the best scavengers, often grows to the size of a golf ball, is very hardy, and has a long life. The pea-sized progeny are bom alive, too big for fish to eat.

   POTOMAC SNAILS. Resembles the Japanese Snail except for three brown stripes running parallel to the spiral of the shell, and sometimes sold as such, but is far inferior. Practically inactive, and does little good.

   LIMPET. Small snail about the size of a match head, with flat, semitransparent shell, rather attractive. Turns up occasionally in pools and aquariums, sometimes in considerable number, having apparently gotten there as a stowaway on some newly purchased aquatic plant. Do what you like with limpets, for they are as harmless as they are useless.

   POND SNAIL. Small, dark snail hardly as large as the end of a little finger. Easily identified because the spiral of the shell is the reverse of that of most other snails, might be called "the snail with the left-hand thread." Breeds prolifically, and the hard shells of the very young protect them from fish. Called the best of all the scavengers, a busy and thorough feeder. The small size enables it to move easily among the more slender plant stems in search of algae, feeding locations that other snails are usually too large and too heavy for.

   RED RAMSHORN. Also called Coral Snail, Copenhagen Red Snail. An excellent scavenger with a large, flattened, orange-red shell shaped like the horn for which it is named. Does quite well in pools, but is particularly popular for aquariums, where it can be seen. Considered the most handsome snail.

   BLACK RAMSHORN. Black-shelled, medium-sized snail, similar in shape to the Red Ramshorn and just as good a scavenger. Quite common in European water gardens and aquariums, but somewhat scarce in the United States.

   WHITE RAMSHORN. Similar to the Black Ramshorn, but with a white shell. Common in Europe, comparatively rare in the United States.