BIOL 2030 Lecture Notes - Lecture 6: Stauromedusae, Cnidocyte, Medusa
30 Jan 2017
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Topic 1: outline jellyfish, sea anemones (chapter 7) Introduction: body forms and structures, cnidae (e. g. : nematocysts, nerve net, feeding, introduction. Gastro vascular cavity with single opening, surrounded by tentacles. Cell called cnidocytes and the cell produces and contains cnidae: singular: cnida, nematocyst a type of cnida, which is an organelle that is produced and contained inside the cnidocytes. Cnidarians fit into one of two morphological types - i. e. dimorphism: polyp morph cylindrical and usually fixed, it represents the asexual stage, medusa morph umbrella-like and usually free swimming, it represents the sexual phase. Fixed, rarely free, found near water mark attached to rocks. Gastro vascular cavity simple without radial and circular canals. Body saucer shaped, umbrella like with a reduced stalk (jellyfish) Statocysts present at the bases of eight adradial tentacles. Gastro vascular cavity represented by stomach, four radial canals and one circular canal. Gastro vascular cavity connects to 4 radial canals, a ring canal and tentacles.
