한국 작약도산 쌍뾰족히드라(자포동물 문: 히드라충 강: 종히드라 과)의 생활사
Life history of Obelia bicuspidata clarke, 1875(Cnidaria: Hydrozoa: Campanulariidae) from Chak-yak island, Korea)
iv, 30 p.
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The research is to study a life history and tissue structures of Obelia biscuspidata Clarke, 1875 of Campanulariidae of hydrozoa. The colonies of O. bicuspidata were collected more than once every month from August 1995 to July 1996 at Chak-yak Island, Inchon. The specimens were placed of water at about 20℃ in growth chamber. Collected samples were preserved with menthol and were fixed with 5% neutral formalin in order to observe the length of every part with light microscope and stereo microscope. For tissue studies the samples were embedded with paraffin and sectioned to 5㎛, dyed with hematoxylin and eosin then observed under a light microscope and photographed. To study the life cycle of the sample, a well developed gonophore polyps were chosen and cultivated in sea water. Obelia bicuspidata was an animal that adhered under hard substratums, rock, shells of bivalvians, fishing line and coral ossicone. The stolon root extende in all directions, and had polysiphonic branch, and monosiphonic branch. While the bell shaped hydranth had bimucronate cusps, gonotheca had cone shaped and matured to release medusa. The body wall of O. bicuspidata coposed of three layers. The outer layer, while the epidermis included muscle cells, interstitial cells and cnidocyte, while the inner layer, gastrodermis included gland cell which secreted digestive enzyme and mucous. Between epidermis and gastrodermis there was a thin and non-cellular mesoglea. The nerve cell was not found in the epidermis and gastrodermis. The medusa of O. bicuspidata was turned inside out, while subumbrella was out. The oral lobe and manubrium was exerted from the center of subumbrella. The sexual maturity development of the medusa took nine days in a growth chamber. Polyp seemed to overlap in many generation every month. The reproduction period turned out to be from May to July. During this period. the differences in the length of hydrotheca, the amount of annulation of hydrothecal pedicel and the length of internode were very clear every month. It is considered that these differences are related with water temperature.