宮入貝Oncomelania nosophora(ROSSON)と水との関係についての実験

抄録

The relation between water and Oncomelania nosophora (ROBSON), an intermediate host of Schistosoma japonicum (KATSURADA), was observed experimentally from season to season (1956〜1957) in the laboratory, the rearing box was conditioned as naturally as possible. In all experiments 50 snails were used. After the snails were kept in water, the hourly changes in their numbers in each section (water, wateredge and grassy land) were recorded. The results are summarized in Text-figs. 3〜7. Under the optimum conditions for snail's activities, large numbers of adults crept out of the water in a short time. When the air temperature was lower than that of the water and the condition of low temperature was not suitable for the snail's activities almost all of them at the wateredge crept into the water. But large numbers of larval snails were remaining and living in the water, and some individuals on the waterside did not go away from the surface of water. Thus, it is a very interesting fact that the larval snails differ from the adults in their behaviour to water.