What is "physa"

Physa \Phy"sa\, n. [NL., fr. Gr. ? a bellows.] (Zo["o]l.) A genus of fresh-water Pulmonifera, having reversed spiral shells. See Pond snail, under Pond.

n. (context zoology English) Any of the genus (taxlink Physa genus) of freshwater snails.

n. any member of the genus Physa

Physa is a genus of small, left-handed or sinistral, air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Physidae.

These snails eat algae, diatoms and detritus.