eing situated in nearly the middle of the occludent
margin. In this respect, and in the shape of the carina and terga, there
is an almost absolute identity with Scalpellum; I may, however, remark
that in Scalpellum, the scuta first grow downwards, and afterwards in
most of the species upwards, whereas here from the beginning, the growth
is both upwards and downwards. In the mouth and cirri, there is rather
more resemblance to Scalpellum than to Paecilasma and Lepas: in habits,
also, this genus agrees with Scalpellum, and if it had possessed a lower
whorl of valves, it would have quite naturally entered that genus. It is
unfortunate, that so insignificant and poorly characterised a form
should require a generic appellation. In natural position, it appears to
lead from Scalpellum through Paecilasma to Lepas.

1. OXYNASPIS CELATA. Pl. III, fig. 1.

Madeira; attached in numbers to an Antipathes; Rev. R. T. Lowe.
Mus., Hancock.

_General Appearance._--The capitulum is rather thin, and broad in
proportion to its length; it seems always entirely covered by the horny
muricated bark of the Antipathes, and hence externally is coloured rich
brown and covered with little horny spines. The membrane over the valves
is very thin, and is with difficulty separated from the Antipathes; it
has, I believe, no spines of its own. The corium lining the peduncle is
a fine purple. All the individuals are attached to the coralline, with
their capitulums upwards in the direction of the branches, and in this
respect fig. 1. is erroneous.

The valves, when cleared of the bark, are white, or are strongly tinged
with pinkish-orange. The upper parts of the scuta and terga are plainly
furrowed in lines radiating from their umbones; hence their margins are
serrated with blunt teeth; their surfaces, moreover, are sparingly
studded with small calcareous points.

_Scuta_ (fig. 1, _a_), sub-triangular, with the lower part rounded and
protuberant, the upper produced and pointed. The umbo is situated in the
middle of the occludent margin, instead of at the rostral angle, as in
the foregoing genera. The occludent margin is straight, and is bordered
by a narrow step or ledge, formed of transverse growth-ridges, and
therefore has its edge serrated: the rostral angle is often slightly
produced into a small projection. The basal margin is short, and forms
an angle above a rectangle with the occludent margin: the tergal margin
is straight; the carina