d therefore the whole does not lie quite in
the same plane; narrow close to the umbo, with a very minute tooth on
the under side; apex rounded. In the upper part, the occludent segments
leave the membranous margin of the orifice, and run in near to the
terga, bending towards them at an angle of 45 deg. with their lower part.
I was unable to distinguish the primordial valves.

_Terga._--These valves are of the most singular shape, resembling a
battle-axe, with a flat and rather broad handle; the upper part consists
of an axe, with a broad cutting crenated edge, behind which is a short
blunt spike. The spike and cutting edge together answer to the double
occludent margin of the tergum in Lepas. The whole valve is flat, thin,
and lies in the same plane; the carinal margin is nearly straight; the
scutal margin bulges out a little, and at a short distance above the
blunt basal point is suddenly narrowed in, making the lowermost portion
very narrow; the widest part of the handle of the battle-axe, is
narrower than the occludent segment of the scuta. The two spikes behind
the cutting and crenated edges of the two terga, are blunt and almost
touch each other; above their point of juncture, the membrane of the
orifice forms a slight central protuberance.

_Carina_, very narrow throughout, concave within, much bowed; upper
point broken and lost, but it must have run up between the terga for
more than half their length; basal portion inflected at nearly right
angles, and running in between, and close below, the linear basal
segments of the scuta, so as almost entirely to cut off internally the
peduncle and capitulum. This lower inflected and imbedded portion, or
disc, gradually widens towards its further end, which is, at least, four
times as wide as the upper part of the carina, and is deeply excised,
but to what exact extent I cannot state, as the specimen was much
broken. On each side of this elongated triangular disc, there is a
slight shoulder corresponding to the ends of the basal segments of the
scuta; and on the upper surface of each shoulder, there is a small tooth
or projection. The middle part of the disc is barely calcified, and is
transparent.

_Peduncle_, rather longer than, and not above half as wide as, the
capitulum; the latter being nearly 2/10ths of an inch in length: the
membrane of the peduncle is thin, naked and structureless.

_Mouth._--Labrum highly protuberant in the upper part, with a row of
beads on