Family: Colorless body; two flagella, one directed anteriorly and the other usually posteriorly; stigma absent.
Genus: Oval, flattened, longitudinally striated; anterior flagellum about four times longer than shorter trailing one; fresh or salt water (How to know the protozoa, 1979).
->> Description at WPRNO Google Image Search
Marsupiogaster sp.
body 24 μm
ant. flag. 59 μm
post. flag. 35 μm
Japan, 1998
Marsupiogaster sp.
body 25 x 15 μm
ant. flag. 50 μm
post. flag. 30 μm
Onnenai
Kushiro marsh
Hokkaido, 2005
Marsupiogaster sp.
body 16 x 9 μm
ant. flag. 40 μm
post. flag. 25 μm
Tochigi, 1998
Movies 
Marsupiogaster sp.
body 18 x 8.5 μm
ant. flag. 43 μm
post. flag. 23 μm
Tochigi, 1999
Marsupiogaster sp.
body 18 x 8.5 μm
Senjo-ga-hara
Nikko
Tochigi, 2003
Marsupiogaster sp.
body μm
Yamakado marsh
Nishi-Azai
Shiga, 2008
