ally a little bowed out of
the plane of the lower part, and abruptly bent at rather above a right
angle along the occludent margin of the orifice. These valves are
situated at about half their own length from the upper points of the
scuta.

_Carina_ considerably arched, extending to the lower points of the
terga, or running up between them for even half their length; equally
narrow throughout; scarcely broader than the terga; both points rounded;
internally concave; the lower point does not extend as far down as that
of the lower lobe of the scuta.

_Peduncle_, narrow, shorter than the capitulum, which, in the largest
specimen was 4/10ths of an inch long. Longitudinal purple bands appear
to have originally existed on the peduncle.

_Filamentary Appendages, trophi and cirri_ all similar to the same parts
in _C. virgata_; but perhaps the anterior faces of the segments in the
posterior cirri are rather less protuberant; perhaps also the first
cirrus is rather shorter in proportion to the sixth cirrus.

_Variety_ (_monstrous_).--Amongst the specimens, I found one very young
one, in which the scuta had not upper lobes, so that in outline they
exactly resembled the scuta in the quite distinct _C. aurita_: there was
not even a rudiment of a carina: the tergum, _on one side_, was
externally bordered by a projecting, semicircular, calcified disc; and
the upper points of both terga showed only traces of the rectangular
projection, which is the chief characteristic of _C. Hunteri_. From
these traces alone, and from the specimen being mingled with the others,
do I here include this variety.

_General Remarks._--I have very great doubts whether I have acted
rightly in considering this as a species; but as there were many
specimens, old and young, all differing remarkably from the common
species, this form anyhow deserves description. The points by which it
can be distinguished from _C. virgata_, are--the almost rectangular
manner in which the upper portion of the tergum is bent outwards and
along the orifice of the sack--the narrowness of all the valves, and
especially of the lateral lobes of the scuta,--and lastly, the greater
curvature of the carina, which in some specimens runs up far between the
terga; had this last character been constant, it would have been an
important one, but such is far from being the case. Great as are these
differences in the valves, and though common to many specimens, they are
not sufficient to c