Quadrulella tropica  Wailes, 1912

Diagnosis: Shell of medium size, hyaline, pyriform, compressed; composed of rectangular siliceous plates ; aperture dilated in broad view, with a shallow notch in narrow view.

Measurements. According to Wailes (1912): Shell length 74—93 µm; breadth 45—60 µm; aperture 20—30 µm; thickness 30—35 µm.

Habitat: Mosses.

Geographical distribution:South America: Argentina; Brazil, Martinique, Peru; Africa: Republic of Congo, Guinea, Ivory Coast, Senegal; Asia: Borneo (Sarawak, Malaysia), Java, Philippines, Sumatra; Australasia: New Guinea (Irian Jaya; Indian Ocean: Seychelles; Europe: the Netherlands, Spain.

Remarks: Wailes (1912): “The arrangement of the plates forming the test is generally more regular near the fundus, where they are arranged diagonally, than near the aperture. In the outline of the test there is a close resemblance to A. militaris but the structure and general appearance are very similar to those of N. scutellata, a species to which it is undoubtedly closely allied. The moss in which this species was first found was collected at Sarawak, Borneo, by J. Brook.”
The specimen which I found resembles much the description and drawing of Q. tropica Wailes, 1912. I found it once in a sample from the Bert Bospad near Hilversum in the Netherlands, in a Sphagnum pool.