he crest.

_Palpi_, oval, outer and inner margins nearly alike, thickly clothed
with spines.

_Mandibles_, with three very strong, yellow teeth; inferior point broad,
coarsely pectinated. In one specimen, on one side, the third tooth was
represented by two smaller teeth.

The _Maxillae_ bear three conspicuous tufts of fine bristles, separated
by larger spines; the first tuft is placed close to the two, upper,
large, but unequally-sized spines; the second tuft is placed in the
middle, and the third at the inferior angle. The two latter tufts stand
on prominences; between the two upper tufts there are three pair, and
between the two lower tufts four or more pair of rather strong spines:
(see the figure, 13, Pl. X, in the allied _P. polymerus_.)

_Outer Maxillae_, with the inner edge divided in the middle by a
conspicuous notch, and with the bristles above and below short, making
two _equal_ combs. On the exterior surface, the bristles are longer and
more spread out. Olfactory orifices prominent, protected by a punctured
swelling between the bases of the first pair of cirri.

_Cirri_, short and rather thick; the first pair is not far removed from
the second. The segments of the three posterior pair are somewhat
protuberant, bearing six pair of short, strong spines, graduated in
length, between which there is a very thick, longitudinal brush of
short, fine, straight bristles, of which the lower ones are the longest;
some thick, minute spines arise from the upper lateral edges of the
segments. The spines in the dorsal tufts are short, much crowded, and of
nearly equal length; see figure, 27, Pl. X, in the allied _P.
polymerus_. In a specimen in which the sixth cirrus had seventeen
segments, the first cirrus had, in the shorter ramus, eight segments, of
which the lower four were thick and protuberant, with the spines doubly
serrated. In this same specimen, the anterior ramus of the second cirrus
had twelve segments, of which the five basal ones were highly
protuberant, and thickly clothed with non-serrated spines. In the third
cirrus the basal segments of the anterior ramus are highly protuberant.
The basal segments in the posterior rami of both these cirri, are
slightly protuberant, but otherwise resemble the segments in the three
posterior pair.

The _Caudal Appendages_ (Pl. X, fig. 22), in full-grown specimens, just
exceed in length the lower segments of the pedicels of the sixth cirrus;
they are nearly cylindrical,