Shell marine, generally small, solid, of an oval conical form, oblong, a
little sloping in front; columella flattened and truncated anteriorly;
right margin furrowed or radiated within, and thickened by a callosity
running to its origin; operculum oval, thin, horny, and sub-spiral.
Planaxis sulcata.
Planaxis undulata.
_P. sulcata._ The furrowed Planaxis. Pl. 27, fig. 4.
Imperforate, furrowed transversely; outer lip crenulated and striated
internally; colour grayish white, spotted with black, forming oblique
longitudinal bands.