(Claparede, 1855)
Spicules 4-winged, 4 main with fine serration, 3-4 times longer than 16 secondary, which are smooth; each with 12-16 long, thread-like myonemes. Diameter of cell body: 0.10-0.16 mm; length of main spicules: 0.7 mm, width at base: 0.009 mm, widest part: 0.012 mm, at top: 0.004 mm; length of secondary spicules: 0.15-0.20 mm, width: 0.004 mm.