per free portion; the growing or corium-covered surface is
transversely oval, and is as wide as the widest part of the terga.

_Rostrum_, exceedingly minute, enlarged at each zone of growth, not so
wide as the immediately subjacent scale on the peduncle.

_Latera_ (fig. 3 _c_), in width equalling two and a half of the upper
peduncular scales, or about one fourth or one fifth of the width of the
carina; growing surface, (or a section parallel to the layers of
growth,) broadly elliptic, pointed at both ends.

_Peduncle_, about twice as long as the capitulum; the scales of the
uppermost whorl are quadrilateral (fig. 3 _d_), and nearly four times as
large as those in the second whorl; these latter are about twice as
large as those in the third whorl, which are very little larger than the
small, almost equal-sized, equally distant, round beads scattered over
the rest of the peduncle, down to the basal cup. All these scales are
dentated, the upper rows most plainly and only on their basal margins;
the lower little beads are very slightly crenated round their entire
margins; they are mingled with star-headed spines (fig. 3 _e_) of yellow
chitine. Basal calcareous discs thin, plainly marked exteriorly by
concentric lines of growth, and covered by the usual yellow membrane,
including the horny, spindle-shaped bodies.

_Size and Colours._--The whole specimen, including the peduncle, was
only one fifth of an inch in length; the capitulum being 3/40ths of an
inch in width. I do not know whether the specimen had attained its full
size, but think this is probable, as a large-sized species would not
have made its habitation in one of the valves of so small a shell as a
Conia. Shell white, exterior membrane, where preserved, yellow, and
bearing small spines. Thoracic segments, the lower segments of the
second, third, and fourth cirri, all the segments of the first cirrus
and the trophi, slightly mottled with darkish purple.

_Mouth._--The teeth or beads on the crest of the labrum are blunt, few,
not very small, and equidistant.

_Palpi_, bluntly pointed.

_Mandibles_, with the three main teeth nearly equal in size; the
pectinations are equal in number, namely, only three between the first
and second, and the second and third main teeth; the inferior angle is
coarsely pectinated, with one central spine much longer than the others;
the distance between the tips of the first and second main teeth, equals
that between the second too