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''Tremoctopus'' is a genus of pelagic cephalopods, containing four species that occupy surface to mid-waters in subtropical and tropical oceans.〔(Tree of Life web project: ''Tremoctopus'' )〕 They are commonly known as blanket octopuses, in reference to the long transparent webs that connect the dorsal and dorsolateral arms of the adult females. The other arms are much shorter and lack webbing. These species exhibit an extreme degree of sexual dimorphism.〔Norman, M.D.; Paul, D.; Finn, J.; and Tregenza, T. (2002). (First encounter with a live male blanket octopus: the world's most sexually size-dimorphic large animal ). ''New Zealand Journal of Marine and Freshwater Research'' 36: 733–736.〕〔Pickrell, John (Aug. 12, 2003). ("Walnut-Size" Male Octopus Seen Alive for First Time ). ''National Geographic News.''〕 Females may reach in length, whereas the tiny males are at most a few centimeters long. The males have a specially modified third right arm which stores sperm, known as a hectocotylus. During mating, this arm detaches itself and crawls into the mantle of the female to fertilize her eggs. The male dies shortly after mating. The females carry more than 100,000 tiny eggs attached to a sausage-shaped calcareous secretion held at the base of the dorsal arms and carried by the female until hatching.〔(Tree of Life web project: ''Tremoctopus'' Eggs, Embryos and Hatchlings )〕 Blanket octopuses are immune to the venomous Portuguese man o' war, whose tentacles the male and immature females rip off and use for defensive purposes.〔Jones, E. C. 1963. ''Tremoctopus violaceus'' uses ''Physalia'' tentacles as weapons. ''Science'' 139: 764–766.〕 Like many other octopuses, the blanket octopus uses ink to intimidate potential predators.〔Thomas, R.F. 1977. Systematics, distribution, and biology of cephalopods of the genus ''Tremoctopus'' (Octopoda: Tremoctopodidae). ''Bulletin of Marine Science'' 27(3): 353-392.〕 Also, when threatened, the female unfurls her large net-like membranes that spread out and billow in the water, greatly increasing her apparent size. ==Species== *''Tremoctopus gelatus'', gelatinous blanket octopus *''Tremoctopus robsoni'' *''Tremoctopus gracilis'', palmate octopus *''Tremoctopus violaceus'', common blanket octopus or violet blanket octopus 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Blanket octopus」の詳細全文を読む スポンサード リンク
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