Page:Scientific results HMS Challenger vol 18 part 1.djvu/951

Rh 2. Acanthometron cylindricum, n. sp. (Pl. 130, fig. 2).

Spines cylindrical, thick and long, at the central base thickened with a pear-shaped knob, and with very small central fulcral pyramid, without leaf-cross. Distal apex rounded or truncated. Central capsule opaque, filled with red pigment-bodies.

Dimensions.—Length of the spines 0.4 to 0.8, breadth 0.01 to 0.015.

Habitat.—Central Pacific, Stations 266 to 274, surface.

3. Acanthometron fuscum, J. Müller.

Acanthometra fusca, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 47, Taf. xi. fig. 4.

Acanthometra fusca, Haeckel, 1862, Monogr. d. Radiol, p. 377.

Spines very thin and long, in the proximal half cylindrical, in the distal half conical, gradually thinned towards the simple conical apex. Central base a small four-sided pyramid, without leaf-cross. Central capsule opaque, filled with brown pigment-bodies.

Dimensions.—Length of the spines 0.2 to 0.4, breadth 0.002 to 0.004.

Habitat.—Mediterranean (Cette, Portofino, Messina).

4. Acanthometron bulbosum, Haeckel.

Acanthometra bulbosa, Haeckel, 1862, Monogr. d. Radiol., p. 377, Taf. xv. fig. 2, Taf. xviii fig. 2.

Spines very thin and long, cylindrical, with simple needle-shaped apex; in the basal part conical, towards the centre much thickened, with a short four-sided fulcral pyramid, without leaf-cross. Central capsule opaque, filled with brown pigment-bodies.

Dimensions.—Length of the spines 0.3 to 0.5, breadth in the middle and outer part 0.001, in the basal part 0.008 to 0.012.

Habitat.—Mediterranean; Atlantic, Station 354, surface.

5. Acanthometron dolichoscion, Haeckel (Pl. 129, figs. 6-8).

Acanthometra dolichoscia, Haeckel, 1862, Monogr. d. Radiol., p. 377, Taf. xviii. figs. 3a, 3b.

Spines very long and thin, cylindrical, in the thickened outer half about twice as thick as in the thin inner half, at the simple apex compressed, two-edged. Central base little thickened, with a small four-sided pyramid, without leaf-cross. Central capsule transparent, whitish or yellowish.

Dimensions.—Length of the spines 0.6 to 0.8, breadth in the proximal part 0.004, in the distal part 0.008.

Habitat.—Mediterranean (Messina, Portofino), surface.

6. Acanthometron conicum, n. sp.

Spines short and thick, conical, gradually thinner from the thick conical base towards the simple apex. Central part of the base with a large fulcral pyramid, but without leaf-cross. Central capsule transparent, colourless (?).

Dimensions.—Length of the spines 0.08 to 0.12, basal breadth 0.02.

Habitat.—North Pacific, Station 244, surface.