The
tectofilosids or
amphitremids are a group of filose
amoebae with shells. These are composed of organic materials and sometimes collected debris, in contrast to the
euglyphids, which produce shells from siliceous scales. The shell usually has a single opening, but in
Amphitrema and a few other genera it has two on opposite ends. The cell itself occupies most of the shell. They are most often found on marsh plants such as
Sphagnum.