(Haeckel, 1887)
Spicules spindle-shaped, tapering from thicker central part towards two thin conical ends, rigid, inelastic; their central part spirally convoluted in very peculiar cochlea-like manner. Ten spicules propped one upon another by central screw. Central capsule dark, opaque. Spicule length: 0.2 to 0.3 mm, breadth of central spiral part: 0.01 mm.