Phylum: Chlorophyta   Family: Hydrodictyaceae

Tetraëdron regulare F.T. Kützing 1845

First described by Kützing (1845: 129). A small and insignificant-looking alga than can be confused with similar algae.
Cell diameters: 30-40 µm.
This small alga is found in the phytoplankton and marginal vegetation in moorland pools and shallow bogs. Infrequently recorded but almost certainly overlooked.

References: 
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition). The Freshwater Algal Flora of the British Isles.
Kützing, F.T. (1845). Phycologia germanica, d. i. Deutschlands Algen in bündigen Beschreibungen. Nebst einer Anleitung zum Untersuchen und Bestimmen dieser Gewächse für Anfänger.