d or is small,
according as the first cirrus is placed near to, or far from the second
cirrus.

_Mouth._--Labrum moderately bullate, with the lower part more or less
produced; crest with blunt, bead-like teeth, and short hairs.

_Palpi_ (Pl. X, fig. 8), acuminated and narrow to an unusual degree.

_Mandibles_, with two or three teeth, and the inferior angle acuminated;
the lateral bristles unusually strong, so as to give the main teeth the
_appearance_ of being pectinated.

_Maxillae_, widely notched, with three great upper spines; the part
beneath the notch projecting, and either straight or irregular.

_Outer Maxillae_, with the inner bristles either continuous or divided
into two groups: exteriorly there is a smaller or larger prominence,
with long bristles. The olfactory orifices are either slightly, or not
at all protuberant.

_Cirri._--In the three posterior pair, the segments have their bristles
arranged in a transverse row, either in the form of a narrow brush, or
consisting only of a single pair with two or three minute, intermediate,
and lateral marginal spines. The anterior ramus of the second cirrus is
thicker, and more thickly clothed with spines than is the posterior
ramus: this latter ramus, however, and both rami of the third cirrus,
are rather more thickly clothed with spines than are the three posterior
pair. The unique case in _A. cornuta_ of the inner rami of the fifth and
sixth cirri being rudimentary (Pl. X, fig. 28) will be minutely
described under that species.

_Caudal Appendages_, thin, tapering, multi-articulate, about as long as
the pedicels of the sixth cirrus.

_Stomach._--The oesophagus runs in a somewhat sinuous course, and enters
the top of the stomach obliquely. There are no caeca. The biliary
envelope presents a reticulated structure, instead of the usual
longitudinal folds.

_Generative System._--The penis is hairy, not very long, and ringed or
articulated in an unusually plain manner; the space between each ring
being about one fourth of the diameter of the penis: the unarticulated
basal portion or support is here remarkably long. The vesiculae seminales
are long, tortuous, and enter the prosoma. The ovarian tubes are of wide
diameter: in _A. cornuta_ they surround the whole capitulum. The
ovigerous fraena are small, constricted at the base, and square on the
free margin, which is studded with minute glandular beads, borne on the
finest footstalks.

_Range._--Souther