Raphidiophrys elegans Hertwig & Lesser, 1874 emend. Penard, 1904

Diagnosis: Scales nearly orbicular to broadly ovate, sometimes oblong; scales often more or less curved with the poles bended downwards; scales 6.2-8.6 x 4.4-6.5 µm with a L/B ratio usually 1.1-1.4, sometimes up to 2.0; scales with internal radial septa; number of septa along the border varying from 30 to 60 per 10 µm; edge of the scales strongly inflected.
Colonial forms show clusters of 2-27 individuals, though light microscopic mounts gave the impression that larger colonies might have broken in two or more sub-colonies, probably due to the transfer of the material by pipetting onto the slides. Colonial and solitary forms show no differentation in shape and structure of the scales.

Dimensions of the scales given by:
Penard (1904): 7.5-8 x 6-6.25 µm, L/B = 1.3,
Wailes (1921): 7-8 x 6 µm, L/B = 1.2,
Hovasse (1964): 7.5-8.0 x 6.0-6.4 µm, L/B =1.2, with a total number of ca. 100 septa along the rim,
Rainer (1968): ex icon.: 5.0-7.5 x 1.5 µm.

Remarks: Raphidiophrys orbicularis Nicholls, 1985, is considered a junior synonym of R. elegans. lts scales tend to be somewhat larger (6-10 µm) but the L/B ratio is 1.1-1.2 (ex. icon.). The total number of septa along the rim varies from 84-96, which agrees with the report of Hovasse (1964).
Scales of R. elegans are distinguished from those R. minuta which lack a curved rim.
I collected this species both in Sweden and the Netherlands. It is rather common.