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Reproduction asexual by fragmentation and sexual by
-
gametes.

- Fertilisation is internal, development indirect.

- eg. Sycon, Spongilla, Euspongiaetc.

Phylum Coelenterata (Cnidaria) –

- Aquatic (marine), Sessile or free living.

- Presence of Cnidoblasts or Cnidocytes – Stinging cells.
- Cnidoblasts are for defence, anchorage or predation.

- Tissue level body organisation.

- Diploblastic.

- Central gastro vascular cavity, single opening mouth.

Two body forms – Polyp (Asexual), Medusa (Sexual)
-
stage.

-
eg Hydra, Physalia, Obelia, Aurelia etc.

Phylum Ctenophora (sea walnuts or comb jellies) –

- Marine, radial symmetry, Diploblastic, tissue grade.