Page:Scientific results HMS Challenger vol 18 part 2.djvu/410

1286 conical, straight wings, of half the length, opposite in pairs in two meridional planes, perpendicular to one another (compare Tetralacorys, Pl. 65, figs. 4, 5).

Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.09 broad.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

2. Sethophæna hexaptera, n. sp. (Pl. 97, fig. 13).

Shell rough, pear-shaped, with distinct collar stricture. Length of the two joints = 1 : 4, breadth = 2 : 4. Cephalis hemispherical, with a conical horn of the same length. Thorax inflate, inversely ovate, nearly pear-shaped, with subregular, circular pores. From its upper half arise, by a broad base, six divergent, strong, conical wings, which are horn-like, curved downwards, and half as long as the thorax.

Dimensions.—Cephalis 0.025 long, 0.04 broad; thorax 0.09 long, 0.08 broad.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

3. Sethophæna enneaptera, n. sp.

Shell rough, with sharp collar stricture. Length of the two joints = 1 : 6, breadth = 1 : 3. Cephalis subspherical, with a stout conical horn of twice the length. Thorax inversely ovate, with pointed, conical, basal part, and irregular, roundish pores. From its middle part arise, by a broad triangular base, nine compressed, divergent wings, which are a little curved, slender, and about as long as the thorax.

Dimensions.—Cephalis 0.025 long, 0.03 broad; thorax 0.17 long, 0.1 broad.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

4. Sethophæna polyptera, n. sp.

Shell thorny, with slight collar stricture. Length of the two joints = 1 : 10, breadth = 3 : 8. Cephalis flat, cap-shaped, without horn. Thorax pear-shaped, with hemispherical base and regular, circular pores. From its lower half (beyond the equator) arises a corona of numerous short conical wings (eighteen to twenty-four), which are a little curved, and divergent downwards, scarcely one-third as long as the thorax.

Dimensions.—Cephalis 0.015 long, 0.04 broad; thorax 0.15 long, 0.12 broad.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

Definition.— (vel Dicyrtida multiradiata clausa) with terminal apophyses. Cephalis with a horn.