Mag. 400x
Large (120µ), filose, testate amoeba. This specimen matches well with C. ampulla keyed out here https://www.arcella.nl/cyphoderia/ and shown here https://www.arcella.nl/cyphoderia-ampulla-2/. The size and association with freshwater aquatic mosses are also characteristic.

• On 3/29/2022 a water and moss sample were taken from the submerged section of a boulder in the Billings-Avery Brook. Air temp. 38F