a buoy to float the individuals, which, when
young and light, were supported on the small objects to which they
originally had been cemented in the usual manner.

[29] Journal of the Acad. Nat. Sc., Philadelphia, vol. vi, p.
138, 1829.

_Filamentary Appendages._--Five on each side, of which four lie in pairs
at the base of the first cirrus (of these, only three are sometimes
developed), and one on the flank of the prosoma.

_Mouth._--Palpi much acuminated. Mandibles with five teeth; the first
not far remote from the second; inferior point rather broad and finely
pectinated. Maxillae with two large, unequal, upper spines, and four
regular steps.

_Cirri._--Posterior cirri, with the upper parts of the segments slightly
protuberant; in young specimens, the spines can be seen to consist of
five pairs, placed in two converging lines in the upper half of each
segment, with numerous minute, latero-marginal, and intermediate little
bristles: in large specimens, all these latter have so increased in
number, that the normal five pair cannot be distinguished, and the front
of each segment is covered by a triangular thick brush of bristles, all
pointing in the same direction, thus giving a very unusual character to
the posterior cirri: the dorsal tuft on each segment consists of six or
seven large spines, with from one to three dozen fine ones. First cirrus
and anterior ramus of second cirrus with broad brushes of bristles. The
pedicels of all the cirri are thickly covered with bristles. _Caudal_
appendages smooth, with rounded summits.

_Penis_ very hairy: vesiculae seminales purple, much convoluted, lying
within the prosoma; testes dendritic, scarcely enlarged at their
terminal points, purplish; ovigerous fraena large with sinuous margins,
the glandular beads being arranged in groups.

_Size._--The largest specimen (from the coast of Devonshire) had a
capitulum 1.6 of an inch long, and 1.2 broad, and of unusual thickness.

_Colours_, after having been in spirits: front surfaces of the segments
of the cirri and of the pedicels purple. In some specimens from off
Borneo, parts of the sack and the interspaces between the two scuta,
were of a fine purple. Montagu states, that the whole shell and body of
animal, when fresh, are pale blue, with the cirri spotted with brown.

_General Remarks._--The extreme variability of this species is
remarkable. In the College of Surgeons, there is a group of specimens
collected by Mr