This is for FYBSc students of University of Mumbai, Maharashtra, India, studying in course one semester I. For further query you may email at sudesh_rathod@yahoo.co.in

1. Course I: First semester
PHYLUM - ASCHELMINTHES
CLASS NEMATODA
(Pseudocoelomate round worms)
1. Multicellular, triploblastic, bilaterally symmetrical and pseudocoelomate worms.
2. Nematodes are endoparasitic or free living found in marine or freshwater.
3. Digestive system is simple but complete.
4. Body is cylindrical and un-segmented and protected with cuticle.
5. Ectoderm is syncytial.
6. Sexes are separate.
7. A typical example is Ascaris (round worm).
Ascaris (a common round worm):
1. Ascaris is endoparasitic found in the gut of
mammals.
2. Body is covered with cuticle.
3. The digestive system is complete with mouth and
anus at opposite ends.
4. Sexes are separate; females are larger than males
and are straight. Males are small and curved at
posterior end. They have genital papilla for
copulation.
5. Female lays about 15000 to 20000 eggs daily which
are passed through fecal matter.
6. Development is direct into rod like larva.
7. Ascaris causes the disease called as ascariasis.
A. M
ale B. Female
Morphology of Ascaris
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Prof. S. D. Rathod Copy No. VI