01 DEFINITION Phylum Coelenterata (Cnidaria) Radially symmetrical, diploblastic multicellular animals with a tissue grade of organisation. Aquatic, freshwater or marine solitary or colonial forms which may be free swimming or sedentary. Locomotion and food capturing: tentacles. Cnidoblasts, nematocysts or stinging cells used for offence and defence. Coelom is absent. Hence, coelenterates are acoelomate animals Reproduction is asexually or sexually. For example, Hydra , sea anemone, jellyfish. 02 DEFINITION Criteria for classification (notochord, segmentation, types of eggs) Notochord Animals with notochord in some stage of their life cycle are known as chordates whereas those which do not develop are called as non-chordates. Body segmentation Segmentation is an architectural body plan in which an organism is built by a series of segments known as metamers. The segments can be both internally and externally. Types of eggs Hom...
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