erga, viewed internally, blunt, owing to the lower carinal margin
being more protuberant than the scutal margin.

Caudal appendages four times as long as the pedicels of the sixth
cirrus: rami of the first cirrus unequal in length by about six
segments.

_Complemental Male_, with a notched crest on the dorsal surface, forming
a rudiment of a capitulum: maxillae well furnished with spines.

Kangaroo Island, South Australia (Mus. Brit., given by Cuvier to
Leach); Adelaide, South Australia (Mus. Stutchbury); King
George's Sound, Voyage of Astrolabe; New South Wales, attached
to a mass of the Galeolaria decumbens, (Mus. Hancock).

HERMAPHRODITE.

All the external parts so closely resemble those of _I. Cumingii_, that
it would be superfluous to describe more than the few points of
difference. The horny substance of both scuta and terga is uniformly
yellow; though in dryed specimens, from the underlying corium being seen
through the valves, these generally have a tinge of blue.

The _Scuta_, viewed internally, are less elongated transversely; they
have their basal margins slightly more hollowed out, and the fold on the
upper free and horn-like portion rather deeper.

The _Terga_, viewed internally, have the apex of the growing or
corium-covered surface higher relatively to the scuta than in _I.
Cumingii_; and the basal angle is much broader, owing to the lower
carinal margin being much more protuberant than the scutal margin. The
spines on the peduncle are all yellowish-brown, and are rather longer
than in _I. Cumingii_. I observed in three or four specimens, that the
lowest part of the peduncle had become _internally_ filled up with the
usual, brown, transparent, laminated cement, cone within cone, so that
this lower part was rendered rigid and stick-like; this latter effect, I
apprehend, is the object gained by the formation of cement within the
peduncle, of which I have not observed any other instance. The entire
length of the largest specimen was one inch; some other specimens were
only half this size.

The thorax and prosoma are of the same shape as in _I. Cumingii_, and in
the largest specimen, about one tenth of an inch square; the prosoma, as
in that species, is hairy. In the _Mouth_, all the parts are closely
similar to those of _I. Cumingii_, but one third larger; the crest of
the labrum is a little roughened with minute points: the palpi are
squarer and blunter at their extremities: the m