抄録
As regards the food habit of the vector snail of Schistosoma japonicum, Oncomelania spp. only few reports are available (Izumi, 1951 ; Ritchie, 1955; Nanking Institute for Parasitology, 1956) . In order to observe the buccal activity of Oncomelania snail directly a simple technic is to be introduced here. By utilizing this technic a certain aspect of the food habit of Oncomelania is able to be elucidated. The mouth opening activity of the snail at that time was observed regardless of the existence of the feeding materials near the proboscis. This activity was named here as mouth opening reaction of Oncomelania. The frequency of this reaction per unit of time can also be utilized for the study of its food habit. Several environmental conditions under which this response is smoothly achieved were also examined.
