Burrows with helicoidal spreiten.
Diagnosis.-In 1855, the following diagnosis of the genus was presented by A. Massalongo: "The leaves simple or branching, linear, tubular, very dense, radial, spirally winding, separated or joined together, at the base converging to a strong phylum of cylindrical or conic shape, rounded, often irregularly rising." (Massalongo, 1855, p. 46).