Page:Scientific results HMS Challenger vol 18 part 2.djvu/760

1636 5. Aulastrum trichoceros, n. sp.

Radial tubes slender, straight, cylindro-conical, about twice as long as the smooth tangential tubes, armed with six to eight verticils of lateral branches, each of which is composed of three short curved branches (similar to those of Aulophacus lenticularis, Pl. 111, fig. 5a). Meshes irregularly polygonal, the majority tetragonal, intermingled with pentagonal and triangular meshes.

Dimensions.—Diameter of the sphere 2.2; tangential tubes 0.12 long, 0.007 broad.

Habitat.—South Pacific, Station 289, depth 2550 fathoms.

6. Aulastrum tetraceros, n. sp.

Radial tubes straight, cylindrical, about three times as long as the smooth tangential meshes, armed with three to six subregular cruciate verticils of branches, each of which is composed of four short, regularly crossed branches, bearing at the end a spinulate knob (similar to those of Aulatractus fusiformis, Pl. 111, fig, 6b). Meshes subregular, square, intermingled with single pentagonal and hexagonal meshes.

Dimensions.—Diameter of the sphere 1.5, of the meshes 0.12 to 0.16; breadth of the bars 0.008.

Habitat.—South Atlantic, Station 318, depth 2040 fathoms.

7. Aulastrum pentaceros, n. sp.

Radial tubes straight, cylindrical, smooth, about as long as the smooth tangential tubes, armed at the distal end with a corona of five curved teeth (of the same shape as in Cannosphæra atlantica, Pl. 112, fig. 6). Meshes subregular pentagonal (intermingled with single tetragonal, hexagonal, and heptagonal meshes).

Dimensions.—Diameter of the sphere 5.0, of the meshes 0.2; breadth of the bars 0.015.

Habitat.—Indian Ocean, Madagascar (Rabbe), surface.

8. Aulastrum polyceros, n. sp.

Radial tubes spindle-shaped, tapering from the broader middle towards both ends, spiny, twice as long as the spiny tangential tubes, armed at the distal end with a corona of twelve to twenty divergent curved teeth (similar to the radial tubes of Auloscena tentorium, Pl. 110, fig. 6). Meshes irregular, polygonal, very variable in size and form. All tubes of this species are armed with scattered, short, conical spines.

Dimensions.—Diameter of the sphere 4.5, of the meshes 0.1 to 0.2; breadth of the bars 0.006.

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