Habitat.—South Pacific, Station 288, surface.
24. Sethoconus setosus, n. sp.
Phlebarachnium setosum, Haeckel, 1881, Prodromus, p. 430.
Cephalis small, subspherical, with distinct collar septum, and the same network as the thorax, with numerous bristle-shaped horns of the same length. Thorax slenderly conical, twice as long as broad, with irregular, polygonal pores of little different sizes, and very thin bars. Surface covered with perpendicular, simple, bristle-shaped spines, about as long as the cephalis.
Dimensions.—Cephalis 0.02 diameter, thorax 0.12 long, 0.22 broad.
Habitat.—Central Pacific, Stations 266 to 272, surface.
25. Sethoconus venosus, n. sp. (Pl. [55], fig. 2).
Phlebarachnium venosum, Haeckel, 1881, Prodromus, p. 430, et Atlas, loc. cit.
Cephalis subspherical, with a stout prismatic horn twice the length, bearing three denticulate edges. The uppermost part of the thorax is supported by three diverging, radial beams arising from the deep collar stricture. Thorax wide, conical, nearly twice as long as broad, with slightly convex, thorny outlines; its delicate network is composed of very irregular, polygonal meshes of different sizes, separated by stronger bars, and of numerous very small polygonal pores separated by very thin bars inside the former. The central capsule of the figured specimen exhibited in the upper third of the thorax four large club-shaped lobes, which arose from a very small sphere enclosed in the cephalis and containing the nucleus.
Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.4 long, 0.3 broad.