キタカミクラゲの眼点による体平衡

概要

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The anthomedusa Polyorchis karafutoensis KISHI-NOUYE has no statocyst but an ocellus is present on the outer surface of each tentacle where it leaves the rim of the bell. The medusa has 96 ocelli and tentacles. It was found that each ocellus sent impulses to the bell muscle, controlled the pulsation, and kept the equilibrium orientation of the animal, in replace of statocysts. The medusa was cut radially and separated into 32 pieces and each piece pulsated normally (35-45 times/min). An individual animal or a separated piece which had at least one ocellus could continue to pulsate, but one in which all the ocelli were removed or selectively injured by the tip of a fine needle could not pulsate. On shading the ocellus, the bell of the medusa pulsated, and an extra systole was recorded on the kymograph, but not the compensatory pause which can be seen in the frog heart. The shadow response of the ocellus was very like the pacemaker of the vertebrate heart conduction system stimulated electrically. The medusa in which only one ocellus was left and the other ocelli were removed inclined nearly as much as 45 degree, the ocellus-free side up and the side with the ocellus down. Medusa in which 4 or 8 ocelli were left radial-symmetrically could maintain normal equilibrated posture and could swim up and down as long as one day.
社団法人日本動物学会の論文
1967-01-15