Species name： Peranema sp.
Bureau of Swerage, Tokyo Metropolitan Goverment
Peranema has a width of 10-70 micrometers and length of 20-40 micrometers. The morphology is cylindrical or wedge shaped. The tip of the cell is round. The rear portion of the cell becomes flattened during swimming. During stationary phase or living in the flock (= agglomerates) water, the morphology of the cells often tends to be rounded. When swimming forward, the cells move smoothly with stretched out flagella forward, the morphology is the normal shape. But when changing the swimming direction, the cell stops and assumes a round shape. In the video Peranema forward is observed to move forward with long flagella
(2015.10.26)