ly separated from the three posterior thoracic segments, by
a band of thin membrane. The tunic of the basal part of the sack, where
it enters the peduncle in a blunt point, is thickened and covered with
roughened rounded papillae. The corium of the sack under the valves, is
coloured (after spirits) so dark a brown as to be nearly black; the
cirri and trophi are similar, but with a tinge of greenish-purple.

_Filamentary Appendages._--Of these there were, on the prosoma of one
specimen, twelve pairs, and in another specimen fourteen pairs, seated
in two approximate rows; the middle filaments are the longest, equalling
about half the diameter of the thorax: each is flattened, and tapers but
little towards its summit, which is roughened with microscopical crests
serrated on both sides; on the summit, also, there are a few bristles
and some very short, thick, minute spines. These appendages are directed
rather towards each other, and towards the thorax. I do not doubt that
their numbers vary according to the size of the specimen. I believe that
they are occupied by testes. Outside these filaments, on each side of
the prosoma, there are two very irregular rows of papillae, intermediate
in length between the filaments and the rounded swellings at the bottom
of the sack. Beneath the basal articulation of the first cirrus, there
is on each side, a short appendage, with a few bristles on its summit.
Lastly, on each side of the middle of the mouth, on the prosoma, there
is a longer appendage, dark-coloured, furnished with a few scattered
bristles on its sides and apex, and directed upwards and a little
towards the adductor scutorum muscle.

_Mouth._--Labrum highly bullate, but with the uppermost part not more
bullate than the lower part, and therefore not overhanging it; basal
margin much produced; crest with some small blunt teeth and some
bristles. The inner fold of the labrum is much thickened, yellow,
punctured, and with a tuft of fine bristles on each side.

_Palpi_, approaching each other but not touching, club-shaped, or with
broad and square extremities, thickly fringed with serrated bristles.

_Mandibles_ with three unusually strong teeth, slightly graduated in
size, with the inferior angle very coarsely pectinated; the lower edges
of the main teeth are roughened.

_Maxillae_, (Pl. X. fig. 13). Spinose edge about half the length of the
mandibles; the two upper spines are unusually strong; close under, and
almost hidd