An organism which lives on or within another organism (the
host), benefits from the relationship, but contributes nothing
beneficial to the host, and may prove to be harmful to the
An obligatory relationship in which one organism (the
parasite) is metabolically dependent on another organism
(the host); the host may be harmed by the relationship.
A host in which the parasite lives a portion of its life cycle but
does not undergo any development.
Reproduction by development of an egg without it being
fertilized by the presence of the male reproductive system.
The production and development of a disease condition.
Ultramicroscopic structures comprising the outer membrane
and structures immediately beneath the outer membrane.
A structure that is an extension of the axostyle which
extends to the extreme anterior end where it forms a support
for the periflagellar lip.
The active engulfment of a particle by a cell.
A facultative, symbiotic relationship where the symbiont
(phoront) is mechanically carried about by its host.
"Cell drinking"; a means of acquisition of fluid nutrients
where minute invaginations are formed in the cell permitting
the nutrients to flow in; then the opening is closed to form a
vacuole containing the nutrients.
The infective larval stage of pseudophyllidean tapeworms;
found in the tissues usually of certain fish and amphibians.
A tapeworm with a strobila containing more than one
The development of a protozoan in the posterior portion of
the intestine or hind gut of its arthropod host.