hern specimen which I examined presented the
following characters: on the prosoma there was a central longitudinal
band, formed of a thin, brittle, brown-coloured calcified layer, which
became irregularly rather narrow towards the thorax; on each side it
sent out six or seven irregular rectangular plates, which surrounded and
supported the bases of the two rows of filamentary appendages; and
outside these, some of the papilliform projections also had their bases
surrounded by small, calcified, separate rings. The thoracic segments
corresponding with the second, fourth, fifth, and sixth cirri had, on
each side, an elongated calcified plate; on the ventral surface of the
thorax, between the first and second cirri, there were two minute
plates. In all the cirri, excepting the first pair, the segments of the
rami, and in the three posterior pairs, the segments of the pedicels,
had their dorsal surfaces strengthened by oblong, quadrilateral,
calcified shields, the upper margins of which are notched for the dorsal
tufts of spine, and the two lateral margins are also slightly hollowed
out; these are represented in figure 27. The lower segments of the
pedicels of some of the cirri, had an additional calcified plate on the
antero-lateral face.

These plates are of a faint-brown or yellowish colour, and are
conspicuous: the degree of calcification differs considerably; some are
quite brittle and very thin, others half horny, and effervesce only
slightly in acids. After having been placed in acid, there is no
apparent difference between the parts before occupied by the calcified
plates and the surrounding membrane; these plates, however, are not
superficial, but consist of several of the laminae, which together
compose the ordinary integument, in a calcified condition. Like the
integuments of the body, and unlike the valves of the capitulum, these
calcified plates are thrown off at each exuviation. Neither the exact
shape nor number of the plates corresponded in different individuals,
nor even on opposite sides of the same individual. The margins of the
plates often have a sinuous corroded appearance; they are, moreover,
often penetrated by minute rounded holes, that is, by minute, rounded,
non-calcified portions. In one specimen from the Antarctic expedition,
there were only here and there a single shield on the segments of the
posterior rami, and no plate on the prosoma. Of two specimens in another
and older set in the British M