from
The Collaborative International Dictionary of English v.0.48
Gregarinae \Greg`a*ri"n[ae]\, prop. n. pl. [NL., fr. Gregarina
the typical genus, fr. L. gregarius. See {Gregarious}.]
(Zool.)
An order of Protozoa, allied to the Rhizopoda, and parasitic
in other animals, as in the earthworm, lobster, etc. When
adult, they have a small, wormlike body inclosing a nucleus,
but without external organs; in one of the young stages, they
are am[oe]biform; -- called also {Gregarinida}, and
{Gregarinaria}.
[1913 Webster]