||Ep`i*zo"ön (?), n.; pl.
Epizoa (#). [NL., fr. Gr. 'epi` upon +
zw^,on animal.] (Zoöl.) One of the
artificial group of invertebrates of various kinds, which live
parasitically upon the exterior of other animals; an ectozoön.
Among them are the lice, ticks, many acari, the lerneans, or fish
lice, and other crustaceans.