Quadrulella scutellata  Wailes, 1912

Diagnosis: Shell moderately large, hyaline, pyriform, compressed; composed of small siliceous, rectangular plates arranged in irregular rows, while smaller rectangular plates may be superimposed at the junctions of the larger plates ; margin of aperture often irregular; plasma and pseudopodia normal; nucleus small with several nucleoli.

Measurements: According to Wailes (1912): Shell length 120—135 µm; width 74—90 µm; aperture 24—30 µm; thickness nearly two-thirds of the width.

Ecology: Sphagnum and wet mosses.

Geographical distribution: Canada, Bolivia, Indonesia, Philippines, Australasia, Europe (?), Galápagos.

Remarks: Wailes (1912): “In the Seychelles it is found without the small covering-plates, but having an admixture, usually 5 to 10 per cent., of circular discs (see image below) in the composition of the tests. It differs from Quadrula symmetrica both in shape and structure of the test. Leidy’s illustration is of an individual, length 140 µm; breadth 100 µm; aperture 30 µm.”