PRECYST
A stage at the onset of encystment of the protozoan
organism where the trophozoite expels any undigested
nutrients it holds and takes on a spherical shape.
PROBOSCIS
A variably shaped hollow, fluid-filled structure at the anterior
end of an acanthoceohalan body. it has a thin muscular
wall, is retractable, and is armed with recurved, scierotized
books.
PROCERCOID
A larval stage of the pseudophyllidean tapeworms which
develops from a coracidium after it enters the first
intermediate host.
PROGLOTTID
One complete segment (reproductive unit) of the strobe] of a
tapeworm.
PROKARYOTE
A cell (such as bacterium) in which the chromosomes are
not contained within a membrane-bound nucleus.
PROMASTIGOTE
A form of Trypanosomatidae which has the kinetoplast and
free flagellum anterior to the nucleus at the extreme anterior
end.
PROTOSCOLEX
The juvenile scolex that buds from the laminated
membranes of a coenurus or hydatid cyst of the genus
Echinococcus.
PROTOZOAN
A single-celled (unicellular) or acellular organism of the
Kingdom Protista which is composed of one or more
membrane-bound -nuclei surrounded by cytoplasm and is
contained within a limiting cell membrane.
PSEUDOCOEL
The interior fluid-filled body cavity enclosed only by the body
wall; not contained within a peritonea] lining.
PSEUDOCYST
A pocket of protozoan organisms within a host cell or
contained by a proliferation of host cells but not surrounded
by a cyst wall of parasite origin.
PSEUDOPHYLLIDEA
An order of the class Cestoidea (tapeworms) characterized
by an almond-shaped scolex with a pair of sucking grooves
(bothiria).
PSEUDOPOD
A temporary extension of the ectoplasm of an amoeba; used
for locomotion and for capture of food.
MD0841
A-16