[17.] Outer maxilla of [Pollicipes mitella], showing the two principal muscles, and the prominent, tubular, (b) olfactory orifices.

[18.] Caudal appendages, and basal segments of the sixth pair of cirri, of [Lepas anatifera]; (a), anus; (b), caudal appendages; (c), lower segment of pedicel of sixth cirrus; (d), upper segment of ditto; (e), basal segments of the two rami.

[19.] Caudal appendage (right-hand side) of [Pollicipes sertus].

[20.] Caudal appendage (right-hand side) of [Scalpellum Peronii].

[21.] Caudal appendage (right-hand side) of [Scalpellum vulgare].

[22.] Caudal appendage (right-hand side) of [Pollicipes cornucopia].

[23.] Caudal appendage (left-hand) [Lithotrya dorsalis]; (a), caudal appendage; (c), lower segment of pedicel of sixth cirrus; (d), upper segment of ditto; (e), segments of one of the rami.

[24.] Portion of caudal appendage of [Lithotrya dorsalis], highly magnified.

[25.] [Pollicipes 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.