Emended diagnosis: From a central node below the point of entry, prostrate branches of rosette diverge radially as highcrested ridges, lowering gradually towards the periphery. Branches diverge in straight lines, at various angles, bear frequent anastomoses, are high and narrow in cross section, and are covered with larger and smaller spiny outgrowths, with dorsal spines ending blindly, whereas the ventral ones form numerous connections with the shell surface.