llicipes polymerus_; anterior ramus of the second cirrus.

26. _Lepas anatifera_; a segment of the sixth cirrus, showing the
arrangement of the spines; (_a_), main anterior spines, of
which there is a corresponding row on the opposite side;
(_c_), dorsal tuft.

27. _Pollicipes polymerus_; a segment of the sixth cirrus, showing
the arrangement of the spines; (_a_), main anterior spines,
of which there is a corresponding row on the opposite side;
(_b b_), calcareous shields on the dorsal surfaces, with
tufts of fine spines near their upper edges.

28. _Alepas cornuta_; sixth cirrus of; (_a_) basal portion of one
ramus, consisting of numerous segments; (_k_), the other and
almost rudimentary ramus.

29. _Poecilasma fissa_; segments of the sixth cirrus, showing the
arrangement of the spines; (_a_), anterior spines; (_c_),
dorsal tufts.

INDEX.

Synonyms and doubtful species are printed in italics.

Abortion, extreme, in the male of Ibla, 202.

_Absia_, 332.

Acari, development of, 18.

Acoustic (?) organs, general description of, 53.

Adductor scutorum muscle, 39.

Affinities of the Lepadidae, 64.

Alepas, Genus, 156.
cornuta, 165.
minuta, 160.
parasita, 163.
_squalicola_, 170.
tubulosa, 169.

Allman, Professor, on Cyclops, 38.

_Anatifa_ vel _Anatifera_, Genus, 67, 99, 215.
_crassa_, 107.
_dentata_, 73.
_elongata_, 374.
_engonata_, 73.
_hirsuta_, 203.
_laevis_, 73, 77.
_oceanica_, 92.
_obliqua_, 264.
_parasita_, 163.
_quadrivalvis_, 203.
_sessilis_, 81.
_spinosa_, 324.
_striata_, 81, 86.
_substriata_, 77.
_sulcata_, 86.
_tricolor_, 77.
_truncata_, 361.
_univalvis_, 163.
_villosa_, 367.
_vitrea_, 92.

Anelasma, Genus, 169.

Antennae, larval, 33.
in the Lepadidae, table of measurements, 286.
of Ibla Cumingii, 191.
of Lepas australis, 15.
of Scalpellum vulgare, 237.

Appendages, caudal, 43.
in larva, 19.
filamentary, 38.

Asplanchna, male of, 292.

Attachment of Cirripedes, 33.
of Scalpellum vulgare, 226.
of Pollicipes polymerus, 310.

Balanidae, affinities of, 64.

Bate, Mr. C. S., on the metamorphoses of Cirripedes, 9-16.

Bopyrus, parasite allied to, 55.

_Branta_, 137.
_aurita_, 141.
_virg