Page:Scientific results HMS Challenger vol 18 part 2.djvu/378

1254 3. Sethopyramis enneactis, n. sp. (Pl. 56, fig. 7).

Cephalopyramis enneactis, Haeckel, 1881, Prodromus et Atlas, pl. lvi. fig. 7.

Shell smooth, slender, pyramidal. Cephalis large, ovate, with pointed apex, nearly hyaline, with very few and small scattered pores. Thorax very slenderly pyramidal, with straight lateral outlines, and nine stout and straight radial beams, which are connected by fifteen to twenty horizontal complete rings. Meshes subregular, square, simple, without secondary network; their length and breadth equally increasing towards the mouth.

Dimensions.—Cephalis 0.05 long, 0.03 broad; thorax (with twenty transverse rings) 0.24 long, 0.1 broad at the mouth.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms.

4. Sethopyramis quadrata, n. sp. (Pl. 54, fig. 2).

Shell smooth, slenderly pyramidal, very similar in form and structure to the preceding species; differing from it in the rudimentary cephalis, which is very small, hemispherical, with few small porules. The three internal cortinar bars of the collar stricture are present; when they become lost this species passes over into Bathropyramis quadrata (Pl. 54, fig. 1).

Dimensions.—Cephalis 0.01 long, 0.02 broad; thorax (with ten transverse rings) 0.15 long, 0.1 broad at the mouth.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Sethopyramis quadratella, Haeckel.

Cornutella quadratella, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. ii. fig. 2.

Litharachnium quadratella, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol, xxxvi. p. 540, Taf. xxxiii. fig. 37.

Shell smooth, broadly pyramidal. Cephalis ovate, small, blunt, hyaline, with very few and small pores (in the figure of Ehrenberg broken off). Thorax broadly pyramidal, with straight lateral outlines, and nine stout and straight radial beams, which are connected by eight to twelve horizontal complete rings. Meshes in the upper half regular, square, in the lower half broad, rectangular (in the tenth transverse row twice as broad as long).

Dimensions.—Cephalis 0.03 long, 0.02 broad; thorax (with ten transverse rings) 0.15 long, 0.15 broad.

Habitat.—Fossil in Barbados.

6. Sethopyramis trapezoides, n. sp.

Shell smooth, broadly pyramidal. Cephalis large, ovate, hyaline, without pores; its collar septum exhibits distinctly the four collar pores (two larger cardinal and two smaller jugular pores).