and flat. Calcareous scales, minute,
symmetrically and closely packed together: each scale is much flattened,
and its shape, including the imbedded portion, is that of a spear with
its point broken off. The basal end of each scale is conically hollow,
and from the layers of growth conforming to this hollow, there is a
false _appearance_ of an open tube running through the scale.

_Attachment._--The surface of attachment is wide: the two cement-ducts,
after running down the sides of the peduncle in a sinuous course, within
the longitudinal muscles and close outside the ovarian tubes, pass
through the corium, and then separately form the most abrupt loops or
folds. These are represented in Pl. IX, fig. 2, in which a space about
1/10th of an inch square is given, as seen from the outside. At each of
the bends, an aperture has been formed through the membrane of the
peduncle, and cement poured forth. The manner in which the discs of
cement (_b_) come out of the two ducts (_a_ _a_), and reach the external
surface, is shown in the section, figure 2 _a'_. The two tubes are
firmly attached to the older layers of membrane, and are covered by the
last-formed layers. In a young specimen, the cement-ducts were a little
above 2/2000ths of an inch in diameter, which had increased, in a
medium-sized specimen, to 5/2000. The cement-glands are retort-shaped,
seated near each other, high up in the peduncle.

_Size._--The largest specimen which I have seen, was three inches in
length including the peduncle; the capitulum was 9/10ths of an inch
long, and one in width.

_Young Specimen._--I examined one with a capitulum 18/1000ths of an inch
long, measured from the lowest whorl to the tips of the terga; the width
was only 13/1000ths of an inch; in old specimens the width of the
capitulum is greater than the length. The length of one of the scuta was
14/1000ths of an inch, therefore, greater than the width of the entire
capitulum, which is not the case with mature specimens. Besides the
scuta and terga, the carina and rostrum, and three pair of large latera,
there was a lower whorl formed of ten or twelve valves, giving
altogether to the capitulum of this very small specimen, either
twenty-two or twenty-four valves.

_Shape of Body, Sack, Colours, &c._--From the position of the orifice of
the capitulum, the animal's body is suspended to the scuta in a more
transverse direction than is usual. The prosoma is well-developed, and
is distinct