2. Spongaster quadratus, n. sp.
Arms at equal distances, forming a regular, rectangular cross, club-shaped, about four times as long as the diameter of the central circular disk, and five times as long as broad at the base. Basal third of the arms square; distal two thirds triangular, three times as broad, with a truncated distal end. Patagium complete, perfectly enveloping the arms, and bordered by an elegant, radially striated, broad edge, forming a regular square. (Similar to Histiastrum quadratum, Pl. [46], fig. 4, but quite spongy.)
Dimensions.—Radius of the arms 0.15, distal breadth 0.06, basal breadth 0.02; length of the square side 0.25.
Habitat.—Pacific, central area, Stations 270 to 274, depths 2350 to 2925 fathoms.
3. Spongaster cruciatus, n. sp.
Arms at equal distances, forming a rectangular, regular cross, lanceolate, three times as long as broad and as the diameter of the central circular disk. Ends of the arms provided with a short conical spine. Patagium incomplete, enveloping only the basal half of the arms, forming a regular square with concave sides.
Dimensions.—Radius of the arms 0.18, greatest breadth 0.05; length of the square side 0.2.
Habitat.—South Pacific, Station 288, surface.
4. Spongaster pentacyclus, n. sp.
Arms at equal distances, forming a rectangular, regular cross, of the same size and form as the circular central disk, so that the dark interior part of the shell is composed of five equal circular disks, situated in a quincuncial manner. The clearer complete patagium, enveloping the whole cross perfectly, forms a regular square with rounded edges.