e minute spines (occasionally forming a tuft)
intermediate between them: on the dorsal surface, in the uppermost part
of each segment, there is a tuft of short spines generally mingled with
some longer, finer ones: on the inner side of each segment, on the upper
rim, there are generally a few extremely minute and short spines. From
the increase of these latter and of the intermediate spines, the
antero-lateral faces of the segments of the first cirrus, and of the
lower segments of the anterior ramus of the second cirrus (Pl. X, fig.
25), are almost always thickly paved with brush-like masses of spines.
The lower segments of the anterior ramus of the third cirrus is
generally, though not always, thus paved: these paved segments are much
broader than the others. The posterior rami of the second and third
cirri are often in some slight degree paved, though in other cases they
resemble the three posterior pair of cirri. The two segments of the
pedicels have bristles on their anterior faces, essentially arranged on
the same plan as on the segments of the rami: the bristles are generally
not so symmetrically arranged on the pedicels of the second and third
cirri, as on the three posterior pair. There are some exceptions to the
foregoing general rules: in the posterior cirri of _Alepas cornuta_,
there is only one pair of long spines to each segment (fig. 28); in
_Dichelaspis Lowei_, there are eight pair; in _Lepas fascicularis_, in
old specimens, the segments are paved with a triangular brush of spines;
the upper segments in _Paecilasma eburnea_ support small oblong brushes;
and, lastly, in _Paecilasma fissa_ (fig. 29), and _crassa_, the spines
form a single circle round each segment, interrupted on the two sides.
These spines are often doubly serrated or plumose: many of them on the
protuberant segments of the first three pair of cirri, are sometimes
coarsely and doubly pectinated.

_Caudal Appendages._--These are present (Pl. X, figs. 18 to 24) seated
on each side of the anus, in all the genera, except in Conchoderma,
Anelasma, and _Scalpellum villosum_; they consist of a very small
single segment, destitute of spines in Lepas, and spinose in Paecilasma,
Dichelaspis, Oxynaspis, Scalpellum, and some species of Pollicipes; they
consist of several segments in Alepas, Ibla, Lithotrya, and in some
species of Pollicipes. In the latter genus, some species have their
caudal appendages multiarticulate, though so obscurely articulated,