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FAQs 1) Write about Hydra. Ans-In Hydra, body is cylindrical and measuring about 1.3 cm in length.Anterior end contains mouth or hypostome, which is crowned with 6 to 10 filiform nematocyst bearing tentacles. Proximal end of the body contains pedal or basal disc or foot meant for attachment to the substratum. Body is diploblastic, consisting of outer ectoderm, inner endoderm and intervening mesogloea. Body wall encloses a gastrovascular cavity extending into the tentacles. 2) Write the position of testes and ovaries in male and female Hydra resectively. Ans- In female Hydra, ovary and buds are found on sides in mid position. In male Hydra 3 or 4 pairs of testes, are found anteriorly and has a fullly grown bud with tentacles on side. Testes are developed near the oral end and ovaries near the base. 3) Give a detailed account on reproduction in Hydra. Ans- It reproduces sexually by fusion of sperms and ova. During asexual reproduction, lateral buds develop on the sides of the body which later on detach and develop into new Hydra . 4) Add a note on colony Of Obelia. Ans- The colony of Obelia looks like a delicate, mossy or fur-like growth, whitish or light brown. It consists of horizontal and vertical filaments. The basal or horizontal anchoring portion of a colony is like a creeping root or complicated meshwork, encrusting over the surface of the substratum. It is called the hydrorhiza or rhizome (Gr., rhizo, root). The hydrorhiza gives off several slender, upright or vertical threads, called hydrocauli. Each hydrocaulus forms the main stem or axis of a colony and measures about 2 to 3 cm in height. 5) Write the position of mouth in polyp and medusa stage of Obelia in its lifecycle. Ans- During the polyp stage, the mouth is situated at the top of the body, surrounded by tentacles, whereas during the medusa stage, the mouth is situated at the distal end of the main body structure.. 6) What is Scyphistoma. Ans- In the life cycle of Aurelia, elongated larva metamorphose into a small trumpt-shaped or hydra like polyp, about 5mm high, without perisarc known as Scyphistoma. 7) Mention the division of body pattern in Sea-anemone. Ans- Body is divided in to three regions in Sea-anemone like-pedal disc, column and oral disc. 8) Write the distribution of Gorgonia. Ans-It is found in South Atlantic and West Indies, Indo-Pacific ocean, Malay Archipelago, Bermuda and Bahamas . 9) Add a note on Polyps or anthocodia in Gorgonia. Ans-In Gorgonia polyps or anthocodia emerge from branches and contain 8 pinnate tentacles, mouth, gastrovascular cavity, 8 gastric filaments and mesenteries. Polyps occur in rows and on two sides only of the stem and its branches.-. 10) Write about pedal disc in Gorgonia. Ans- In Gorgonia the base of the colony is expanded to form a hold fast organ called as pedal disk.