y consist of four prominent ridges proceeding
from the umbo, and united together for part only of their length, and,
therefore, ending in four prominences; one of these, the longest, has
the same width throughout, and forms the basal point; a second, very
small one, is seated high up on the carinal margin just above the apex
of the carina; the third and fourth, are nearly equal in length, and
project one above the other on the scutal margin. There are two
occludent margins, meeting each other at right angles, and forming a
prominence, as in Lepas; and this gives to the margin of the valve the
five prominences. The whole valve internally is flat; externally, it is
ridged as described.

_Carina_ (fig. 10, _a_, _b_), much bowed, narrow, long; externally, the
central ridge is quite flattened; internally, slightly concave, but
scarcely so towards the lower part, which is narrow; the upper part
widens gradually, and the apex is rounded. The basal embedded portion is
as wide as the uppermost part, and forms a cup, unlike anything else
known: the outline of this cup is semi-oval and crescent-formed; it is
moderately deep; it is formed by the external lamina of the carina
bending rectangularly downwards and a little outwards, whereas the inner
lamina of the lower part (which is slightly concave), is continued with
the same curve as just above, and forms the concave chord to the
semi-oval rim of the cup. This cup, I believe, lies under the points of
the basal segments of the scuta.

_Peduncle_ unknown, probably short.

_Length_ of capitulum, above 2/10ths of an inch.

_Mouth._--Labrum with the upper part highly bullate, and produced into a
large overhanging projection; crest with a row of rather large bead-like
teeth; _palpi_ small, their two sides parallel, very sparingly covered
with long bristles.

_Mandibles_, narrow, produced, with four teeth, and the inferior angle
produced into a single strong spine: the distance between the tips of
the first and second teeth almost equals that between the tip of the
second tooth and of the inferior angle.

_Maxillae_ with three large upper unequal spines, beneath which, there is
a deep and wide notch (bearing one spine), and the inferior part
projects highly, bearing three or four pairs of spines, and is, itself,
obscurely divided into two steps.

_Outer Maxillae_, very sparingly covered with bristles; outline,
hemispherical.

_Cirri._--The rami of the five posterior pair are ex