Growth form encrusting, few mm thick and few cm in diameter. Consistency jelly-like or softly colloidal. Surface smooth with small oscular tubes and not evident inhalant apertures. Colour in vivo pale yellow to dark yellowish, sometimes with more or less dark blue tonalities. Absence of horny skeleton. Flagellate
chambers radially arranged around the aquiferous system canals, elongated and typical of the genus (25 µm in diameter, 60–150 µm in length).