Darting and dashing
A large ciliate whose whole surface is densely covered with cilia is darting around. It pauses for an instant and then dashes into a group of particles. This violent activity disturbs the peaceful habitat occupied by small algae and flagellates.
Commentary by Prof. Yuji Tsukii, Hosei University
This organism belongs to genus Frontonia. From its long, flat body, it may be Frontonia leucas.
In the first part of this video (0:06~), the organism is opening its mouth toward a glass surface, probably because it found some kind of food there. Later it gives up and swims away. In fact Frontonia swallows similar-sized diatoms, which can be seen in the following link.
Sampling Date : 08 August 2009
Sampling Site : Hirose River A Google Map