Marine Biological Studies on Bivalve-Inhabiting Hydrozoans in Southern Japan, especially in Islands washed by Kuroshio

1.对马群岛中的日本真海蜇的中间型水母从宿主双壳类中释放的时间在夏季和冬季之间存在差异。2.广岛县竹原的南方型水母全年都与紫球藻共生，除冬季外，其繁殖期较长; 3.广岛县竹原的南方型水母在冬季较早停止繁殖，但在冬季较晚停止繁殖。广岛的水母在傍晚前后的几个小时内释放，呈现出一个日周期性。4.将取自白滨的日本真水母（Eug.japonica）在不同盐度条件下进行养殖。在75%和50%的水温条件下，水母芽不能发育，水母不能进食。5.将日本真水母（Eug.japonica）的水母与其寄主-在较低的温度下，1周后它们停止释放水母，水螅的下质体缩小。6.翡翠贻贝是日本真海蜇的新寄主。7.对马群岛的菲律宾蛤仔（Ruditapes philippinarum）与真裸藻（Eugymnanthea sp.）的珊瑚虫发生共生的第二个记录。然而，对水螅的鉴定失败了，因为没有通过饲养它们获得水母。

1.Release time of medusae of the intermedia form of Eutima japonica taken from the Tsushima Islands from the host bivalve, differed between summer and winter seasons. In winter, Eugymnanthea japonica ceased to release its medusae earlier than Eut.japonica.2.The southern form of Eut.japonica taken from Takehara, Hiroshima was commensal with M.edulis galloprovincialis throughout the year, and its breeding occurred for a long period except for winter.3.The southern form of Eut.japonica taken from Takehara, Hiroshima showed a daily periodicity that the medusae were released in a few hours around evening.4.The polyps of Eug.japonica taken from Shirahama were reared under the different conditions of salinity. Under the 75% and 50% conditions, no medusa buds were developed and the polyps became to be impossible to feed.5.The polyps of Eug.japonica were reared under the different conditions of water temperature together with their host, M.edulis galloprovincialis. Under the lower temperature, they ceased to release the medusae after one week, and the hypostome of polyp was reduced.6.Perna viridis was found to be the new host bivalve of Eug.japonica. The commensalism was found never in larger individuals of the bivalve but only in the smaller ones.7.The second record of the commensalism of polyps of Eugymnanthea sp.with a bivalve, Ruditapes philippinarum was taken from the Tsushima Islands. The identification of the polyps, however, was failed, because no medusae were obtained by rearing of them.