A ciliate-like organism is sticking its head into aggregate. Various types of diatoms come in and out of the aggregate, pushing against this unknown organism.
Commentary by Prof. Yuji Tsukii, Hosei University
The shape of this organism does not change at all, and even the cytoplasm inside does not move.
This unidentified organism surrounded by a shell has possibly died, and it is difficult to say what it is because the front of the cell is behind a particle.
If its shell has an opening at the front, it could be in the genus Euglypa.
Sampling Date : 03 July 2009
Sampling Site : Hirose River B Google Map