Page:Scientific results HMS Challenger vol 18 part 1.djvu/788

580 1. Spongolonche conostyla, n. sp..

Spongy disk circular, with irregular framework, without concentric rings. Both opposite radial spines conical, about as long as the radius of the disk, and four times as long as broad at the base. Margin of the disk nearly smooth.

Dimensions.—Diameter of the disk 0.16; length of the radial spines 0.18, basal thickness 0.045.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

2. Spongolonche amphistyla, n. sp.

Spongy disk circular, with four to six concentric rings in the inner part, with quite an irregular framework in the outer part. Both opposite radial spines cylindrical, twice to three times as long as the diameter of the disk, at the base about as broad as two meshes of the framework. Margin of the disk ciliated.

Dimensions.—Diameter of the disk 0.2; length of the radial spines 0.4 to 0.6, basal thickness 0.01.

Habitat.—Pacific, central area, Station 271, depth 2425 fathoms.

Definition.— with three solid radial spines on the margin of the circular or triangular disk.

The genus Spongotripus is characterised by three marginal spines, which are commonly regularly disposed, more rarely in a bilateral or an irregular manner. It corresponds to Trigonocyclia among the Coccodiscida, to Tripodictya among the Porodiscida.

Definition.—Radial spines of equal size and distance; triangle regular.

1. Spongotripus regularis, n. sp.

Spongy disk circular; three radial spines on its margin of equal size and equidistant, strong, conical, about as long as the diameter of the disk, and five times as long as broad at the base.

Dimensions.—Diameter of the disk 0.15; length of the spines 0.16, basal breadth 0.03.

Habitat.—Pacific, central area, Station 272, surface.