BIOL 121 Lecture Notes - Lecture 18: Hydrostatic Skeleton, Cnidocyte, Manowar
12 Apr 2015
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Document Summary
Can be found as a polyp (hydra, anemone) or medusa (jellyfish) Obelia marine, colonial polyps, tiny sexual medusae. Physalia portuguese man-o-war, colony with long tentacles. Aquatic freshwater lakes and streams in. Chemoheterotrophic predator, preys on small invertebrates in water. Cnidoblasts specialized stinging cells that contain nematocytes (sticky or poisonous harpoons) used to trap prey. Tentacles extendable structures that house the cnidoblasts. Muscle fibres for some movement, nerve net for sensory response, basal disc to attach to rocks/plants. Closed gastrovascular cavity acts as a hydrostatic skeleton. Sessile (mainly) but can move very slowly across surface of rocks/plants.
