7. Spongasteriscus tetraceros, Haeckel.
Spongasteriscus tetraceros, Haeckel, 1862, Monogr. d. Radiol., p. 475.
Arms at different distances, forming a bilateral or irregular cross, grouped in two opposite pairs; their form isosceles triangular; their length larger than the radius of the large elliptical central disk, which exhibits in the interior six to twelve concentric rings.
Dimensions.—Radius of the arms 0.16, of the central disk 0.1; basal breadth of the arms 0.06.
Habitat.—Mediterranean (Messina), North Atlantic (Canary Islands), surface.
8. Spongasteriscus myelastrum, n. sp.
Arms at different distances, forming a bilateral or irregular cross, grouped in two opposite pairs; the arms of one pair broader and shorter than the arms of the other pair. Each arm in its basal half simple, in the distal half forked; ends of the fork branches blunt. In the central disk no concentric rings. (Similar to Myelastrum octocorne, Pl. [47], fig. 12, but quite spongy.)
Dimensions.—Radius of the arms 0.2, basal breadth 0.05, distal breadth 0.02.
Habitat.—North Pacific, Station 236, surface.