Arcella is a genus of testate amoebae in the order Arcellinida, usually found in freshwaters and mosses, and rarely in soils. A key characteristic of Arcella is the circular test with a hole on its center from where finger-like pseudopods emerge.

Arcella is a genus of testate amoebae and one of the largest and most common testacean genera. Over 50 species, subspecies and varieties have been described, but many descriptions are not adequate or based on artificial criteria.

Arcella is one of the most frequently encountered of the testate amoebae, especially in highly organically polluted waters, and in the sediments on the pond's bottom, where plant materials rot under conditions of low oxygen concentration.

Arcella vulgaris Ehrenberg, 1830 Diagnosis: Shell hemispherical, helmet-shaped, with a distinct basal edge; height of the shell about one-half the diameter. Surface smooth; aperture invaginated, circular, with recurved collar; cytoplasm with epipodia attached to the shell; usually with two vesicular nuclei.

Species of Arcella can be found in all freshwater biotopes, wet and dry mosses and, with a few species, in soils. Some species are characteristic for specific habitats – e.g. Arcella arenaria is common in dry mosses and Arcella artocrea pseudocatinus in wet Sphagnum .

A quick guide to arcella. Key: Shell color transparent or yellowish 2. Shell circular or disk-shaped 3. Shell diameter 80-100 µm, slightly flattened Arcella vulgaris 3. Shell diameter 30-50 µm, more...more ↓

The Arcella is a small amoeba and belongs to the Phyllum Sarcodina. It lives in a light brown or transparent chitinous "test" (shell). It is dome like on the top and concave on the bottom.

…the inner layer (as in Arcella), sand or solid particles glued together (as in Difflugia), or siliceous plates that are secreted by cytoplasm, pushed out, and cemented in place (as in Euglypha). The genus Nebela forms its pear-shaped shell from the plates of other testaceans ingested as food.

Apr 24, 2021 · Arcella is a genus of Amoebozoa from the Protista Kingdom, made up of eukaryotic unicellular organisms that have a characteristic and distinctive element, a kind of cover or shell that covers the entire cell and provides protection.

Arcella is a genus of testate amoebae in the order Arcellinida, usually found in freshwaters and mosses, and rarely in soils. A key characteristic of Arcella is the circular test