Class Hydrozoa - Epidermal cells are termed...

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Class Hydrozoa: Hydras and Portuguese Man-of-war ( Physalia ) The polyp stage is dominant in members of this taxonomic class. The Portuguese man-of-war is a colony of polyps, with the original polyp becoming a gas-filled float. Other polyps specialize for feeding or reproduction. The Portuguese man-of-war can cause serious injury to swimmers since each tentacle (in reality a string of individual organisms) has numerous nematocysts. Hydra , shown in Figure 14, are solitary, freshwater hydrozoan polyps. The body is a small tube about one-quarter inch long, best observed with a dissecting microscope. Four to six tentacles surround the mouth, the only opening at into the body. Hydra can move from one location by gliding or even somersaulting. Hydras have both muscular and nerve fibers, and respond to touch.
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Unformatted text preview: Epidermal cells are termed epitheliomuscular cells and contain muscle fibers. Cnidocytes and sensory cells are also present in the epidermis. Interstitial cells can produce an ovary or testis , and may assist regeneration. Gland cells secrete digestive juices into the gastrovascular cavity into which tentacles have stuffed captured prey. Digestion is completed within food vacuoles of nutritive-muscular cells. Nutrients diffuse to the rest of the body. Hydras reproduce both sexually asexually (by budding). In sexual reproduction, sperm from a testis swim to an egg within an ovary. Following early development within the ovary, a protective shell forms and allows the embryo to survive until conditions are optimum. Hydra are commonly utilized animals in biology labs....
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Class Hydrozoa - Epidermal cells are termed...

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