Page:Scientific results HMS Challenger vol 18 part 1.djvu/790

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Definition.— with four solid radial spines on the margin of the circular or square disk, commonly crossed in two equatorial diameters perpendicular one to another.

The genus Staurodictya exhibits four marginal spines in cross form. Commonly the cross is regular and rectangular, the four spines being opposite in pairs in two perpendicular diameters; sometimes more or less irregular. The genus repeats Staurodictya among the Porodiscida, Staurocyclia among the Coccodiscida.

1. Spongostaurus cruciatus, n. sp.

Spongy disk circular; four radial spines on its margin opposite in two crossed equatorial diameters, perpendicular one to another, conical, about as long as the diameter of the disk.

Dimensions.—Diameter of the disk 0.16; length of the spines 0.18, basal breadth 0.04.

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

2. Spongostaurus serratus, n. sp.

Spongy disk circular; four crossed radial spines very large, twice to three times as long as the diameter of the central disk, serrated on both edges, with two rows of strong conical perpendicular teeth (similar to the saw of Pristis antiquorum).

Dimensions.—Diameter of the disk 0.1; length of the spines 0.2 to 0.3, breadth 0.02.

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

3. Spongostaurus hastatus, n. sp.

Spongy disk square, with concave sides; four crossed radial spines cylindrical, on the broader distal end spear-shaped or nearly lanceolate, one and a half times as long as the diameter of the disk.

Dimensions.—Diameter of the disk 0.13; length of the spines 0.2, basal breadth 0.01, distal breadth 0.03.

Habitat.—Tropical Atlantic, Station 347, surface.

4. Spongostaurus quadratus, n. sp.

Spongy disk square, with rectilinear sides; four crossed radial spines pyramidal, arising from the corners of the square, about as long as its half diagonal.

Dimensions.—Diameter of the disk 0.16; length of the spines 0.08, basal breadth 0.02.

Habitat.—Pacific, central area, Station 271, surface.