Phylum: Chlorophyta   Family: Scotinosphaeraceae

Scotinosphaera paradoxa G.A. Klebs 1881

First described and illustrated by Klebs (1881: 300, pl. 4: 55-63). It has changed its name a couple of times in the interim but now reverted back to the original. John et al. (2011: 477, as Chlorochytrium facciolae (Borzì) Bristol 1920) describe it as “Cells spherical, ellipsoid or irregularly shaped, … walls thick and stratified; …”
Cell dimensions: Diameter: 26-42 µm.
Status unknown in the Outer Hebrides, possibly scarce. Found in circum-neutral waters with other algae.

References: 
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition). The Freshwater Algal Flora of the British Isles.
Klebs, G.A. (1881). Beiträge zur Kenntniss niederer Algenformen.