The cell body of centrohelid heliozoans is covered with a layer of scales. These scales have species-specific morphology and,
since they present in the trophic stage of the cell cycle can be termed “trophic” scales. Several species are known to form cysts; during this
process they can produce specific “cyst” scales, different from trophic scales. The present paper describes morphology of cyst scales in two
species of centrohelid heliozoans: Raineriophrys erinaceoides and Raphidiophrys heterophryoidea. The latter species has two types of cyst
scales: scales of the first type resemble trophic scales in general structure but, their borders are broad, flattened and not enrolled. Scales of
the second type are polygonal and connected to each other by special teeth, forming a single layer organized in a jig-saw puzzle-like manner.
In Raineriophrys erinaceoides only one type of cyst scale was found. These scales are polygonal and completely different from trophic
scales. It is unclear whether these scales form a puzz