Habitat.—South Pacific, Station 300, surface.
3. Distriactis alterna, n. sp.
Disk smooth, five times as broad as the medullary shell, about twelve pores on the radius. Six marginal spines pyramidal, at equal distances, but unequal alternating size; three larger (perradial) spines as long as the shell radius, three smaller between them (interradial) half as long and broad.
Dimensions.—Diameter of the disk 0.15, of the medullary shell 0.03; length of the three major spines 0.08, of the three minor 0.05.
Habitat.—North Atlantic, Station 353, surface.
4. Distriactis palmantha, n. sp.
Disk rough, four times as broad as the medullary shell, about ten pores on the radius. Six marginal spines conical, at equal distances, but unequal alternating size; three larger (perradial) spines as long as the shell diameter, three smaller between them (interradial) as long as the radius.
Dimensions.—Diameter of the disk 0.2, of the medullary shell 0.05; length of the three major spines 0.2, of the three minor 0.1,
Habitat.—South Atlantic, Station 325, surface.
5. Distriactis amphithecta, n. sp.