Ĭn'fu-sō'ri-ȧ, n. pl.

Ĭn'fu-sō'ri-ȧ, n. pl. [N. Lat., from infundere, infusum; Fr. infusoires. See INFUSE.] (Zoöl.) Microscopic animals found in water and other fluids, and multiplying by gemmation.

☞ They move by means of cilia, have no shell or crust, and seem to be composed of sarcode. Neither nerves, muscles, nor organs of sense have been found in them, nor has any distinction of sex been observed. They have been considered as forming a class of protozoa, but many of them have been found to be forms of the alternate generation of higher groups. They are called infusoria because found in infusions when left exposed to the air for a time. Dana.