ay above the top of the peduncle. The
occludent segment is bluntly pointed; it is directed a little inwards
from the edge of the orifice towards the terga; the apex reaches up just
above the slightly reflexed lower point of the terga. The adductor
muscle is fixed under the point of junction of the two segments.

The _Terga_ are battle axe-shaped, with the blade part very prominent,
smooth-edged; behind the blade there is a short upwardly-turned
prominence. The lower point of the handle of the axe, is bent towards
the carina. The tergum, measured in a straight line, equals in length
two thirds of the occludent segment of the scutum, the handle being
rather narrower than this same segment.

The _Carina_ is extremely narrow and much bowed; the apex reaches up
only to just above the lower bent points of the terga. The basal end is
rectangularly inflected, and stretches internally nearly across the
peduncle; it consists (fig. 7 _a_) of a triangular disc of yellow thin
membrane, four or five times as wide as the upper part of the valve; the
end of this disc is hollowed out; its edges are thickened and calcified,
and hence, at first, instead of a disc, this lower part of the carina
appears like a wide fork; the tips of the prongs stretch just under the
tips of the basal segments of the scuta.

_Peduncle._--Its narrowness and transparency are its only two remarkable
characters.

_Mouth._--All the parts closely resemble those of _D. Grayii_, but being
in a better state of preservation I will describe them. The labrum is
highly bullate, with a row of minute teeth on the crest, placed very
close together in the middle. Palpi small, thinly clothed with spines;
mandibles extremely narrow, hairy, with four teeth, but the lower tooth
is so close to the inferior angle, as only to make the latter look
double. Maxillae, with a very deep broad notch, dividing the whole into
two almost equal halves; in the upper part there are three main spines.

_Cirri._--The first pair are placed at a considerable distance from the
second pair; they are short with equal rami, and rather broad segments
furnished with a few transverse rows of bristles. The five posterior
cirri have singularly few, but much elongated segments, bearing four
pair of spines: the two rami of the second pair are alike, and differ
only from the posterior cirri in a few of the basal segments having a
few more spines.

The _Caudal Appendages_ are twice as long as the pedicels