_Parietes pale pink; radii rather darker. Scutum with a small articular
ridge. Tergum with the longitudinal furrow very shallow and open; basal
margin on both sides sloping towards the spur._
_Hab._--New Zealand. Mus. Brit., and Flower: attached to shells.
_General Appearance._--Shell conical or tubular, with a large
rhomboidal orifice; very pale pink, but tinted yellowish from the
persistent epidermis, and sometimes faintly striped longitudinally;
radii and sheath of rather a darker pink; scuta in themselves white,
though lined by purple corium; the carinal half of the tergum pink.
Walls extremely smooth. Largest specimen above one inch in basal
diameter.
_Scuta_, with the finest striæ radiating from the apex; growth-ridges
moderately prominent; articular ridge small; there is a very slight
and blunt adductor ridge: the hollow for the lateral depressor muscle
is rather narrow and deep.
_Terga_, with the apex slightly prominent or beaked; the longitudinal
furrow is of very little depth; on its scutal margin there is a
narrow, rounded, slightly prominent ridge, which, however, appears
more like a furrow than a ridge. Spur moderately long and blunt;
placed at half its own width from the basi-scutal angle; the
basal margin on both sides of the spur, slopes gently towards it.
Internally, the articular ridge is pretty well developed; the scutal
margin is not much inflected; the carinal portion of the under
surface of the valve is rough; the crests for the carinal depressor
muscle are entirely absent.
_Compartments._--Walls moderately strong; parietal tubes small, with
transverse septa in their upper ends; inner surface of the walls much
less strongly ribbed than is usual. _Radii_ broad, with their summits
parallel to the basis; their septa are strongly denticulated. _Alæ_
with their summits oblique; their sutural edges are barely crenated.
_Basis_, thin, flat, or cup-formed. _Body_ unknown.
_Affinities._--In general appearance this species comes near to _B.
psittacus_; but in all essential characters it comes much closer
to the following species, from which, however, it can easily be
distinguished by colour, and by the inner lamina of the parietes not
being cancellated.