Havelockia

Pearson, 1903

26 species

ten tentacles. The calcareous ring is constructed with long forked tails. In the body wall there are tables with 2 columns. Differs from Thyone because in the introvert, there are tables but no rosettes. (Panning, 1949)

Calcareous ring compact, has long forked tails which consist of several large pieces. (Panning, 1949. Supplement)

Calcareous ring short, stout, only anterior projections of radial and interradial plates free; posterior paired processes of radial plates divided into several pieces. Body wall spicules tables with squarish to oval discs usually perforated by four large central and four smaller peripheral holes, the latter sometimes reduced or absent; spire of two pillars joined at apex and terminating with a few blunt teeth. (Thandar, 1989)