Shell thick walled, with irregular, roundish pores, three to six times as broad as the bars; eight to nine on the radius. Forty to sixty radial spines, about as long as the diameter of the shell, three-sided prismatic, not straight, but more or less bent.
Dimensions.—Diameter of the shell 0.12, pores 0.005 to 0.012, bars 0.0015 to 0.02; length of the spines 0.12, breadth 0.003.
Habitat.—Mediterranean (Messina), surface, Haeckel.
30. Acanthosphæra gibbosa, n. sp.
Shell thin walled, rugged or tuberculate, covered by about twenty hill-shaped tubercles or protuberances with flat valleys between them. Network very delicate, with thread-like bars and irregular, polygonal pores; twenty to thirty on the radius. Radial spines very numerous, bristle-shaped, twice to three times as long as the diameter of the pores.
Dimensions.—Diameter of the shell 0.3, pores 0.01 to 0.02; length of the spines 0.02 to 0.05.
Habitat.—Central Pacific, Station 274, surface.
31. Acanthosphæra reticulata, n. sp. (Pl. [26], fig. 5).
Rhaphidosphæra reticulata, Haeckel, 1881, Prodromus.
Shell thick walled, with irregular, roundish pores, twice to four times as broad as the bars; six to eight on the radius. Surface of the bars covered with a peculiar delicate network of very fine crests. Twenty to forty radial spines, angular, pyramidal, scarcely one-third as long as the radius of the shell, as broad at the base as the bars.