Species in which the aperture is sub-oval, and the external edge excavated; spire short, base triangular; columella rugose; outer lip thickened.
C. areola. The draught-board Cassis.
Smooth, shiny, white, with square orange tesselated spots; spire short and conical, with decussated striæ; lower part of columella rugose.
3. Ricinula. Nine species.
Shell oval or sub-globular, thick, armed with points or tubercles, with a depressed spire; aperture narrow, elongated, notched, sometimes canaliculated anteriorly, and digitated externally; the left edge more or less callous, sometimes denticulated; operculum horny, oval, transverse, with elements slightly imbricated.
Ricinula horrida.
R. clathrata.
R. arachnoidea.
R. miticula.
R. digitata.