Section II. PHYLUM ACANTHOCEPHELMINTHES
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GENERAL DESCRIPTION
This phylum was once considered a class of the phylum Aschelminthes. The
species in this phylum are all parasitic and there are two potential pathogens to man:
Macracanthorhynchus hirudinaceus, and Moniliformis moniliformis. They are commonly
known as thorny headed worms. Some writers believe that this phylum is an
evolutionary link between the flat and the round worms. The worms have an anterior
retractile armed proboscis with 5 to 6 rows of spines. The digestive tract is absent and
they absorb nutrients through the skin. The cuticle is folded and creased showing some
pseudosegmentation. Only Macracanthorhynchus hirudinaceus will be presented in this
text.
Figure 4-39. Morphology of Acanthocephalans.
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