jacent scales of the peduncle; (_b_),
scutum; (_c_), tergum; (_d_), carina.

2. A portion (about 1/10th of an inch square) of the surface of
attachment of the peduncle of _Pollicipes polymerus_, seen
from the outside, greatly magnified, showing the small
circular (_bb_) patches of cement, poured out from the
cement-ducts (_aa_) which lie within the peduncle.

2_a'._ A portion of a section, still more magnified, through the
basal membrane of the peduncle, through one of the loops of
the cement-ducts (_aa_), and through one of the circular
patches (_b_) of cement.

3. Cement gland, duct, and ovarian tubes of _Conchoderma aurita_;
(_aa_), ovarian tubes, with ova in process of formation;
(_b_), cement-gland; (_c_), cement-duct.

4. _Conchoderma virgata_, enlarged, with one side of the capitulum
and of the peduncle removed, to show the form and position
of the body.

(_a._) tergum, edge of.

(_b._) mouth, with one of the palpi seen on the inner, upper
corner.

(_c._) adductor scutorum muscle.

(_d._) orifice of acoustic (?) sack.

(_e._) scutum, occludent margin of.

(_f._) branching ovarian tubes within the peduncle.

(_g._) filamentary appendage on the prosoma.

(_h._) ditto, close to basal articulation of the first
cirrus.

(_i._) ditto, on the pedicel of the first cirrus.

(_j._) ditto, on the pedicel of the third cirrus.

(_k._) ditto, on the pedicel of the fourth cirrus.

(_l._) ditto, on the pedicel of the fifth cirrus.

(_m._) edge of the carina.

(_n._) prosoma.

5. Apex of one of the filamentary appendages of _Conchoderma
aurita_, greatly magnified, exhibiting the included
branching testes.

6. Acoustic (?) sack of _Conchoderma virgata_, taken out of the
acoustic meatus, with the diaphragm from the summit removed;
greatly magnified.

7. Terminal part (magnified seven times), of the peduncle of an
elongated specimen of _Scalpellum vulgare_, slit open, with
the corium removed, showing the two cement-ducts (_aa_), and
a row of circular patches (_bb_) of cement, by which the
peduncle, along its rostral edge, is attached to the thin
horny branches of the coralline. The larval antennae