Actinomma sphærechinus, Haeckel, 1879, Atlas (pl. xxix. fig. 2).
Cortical shell thin walled, with irregular, roundish pores, twice to five times as broad as the bars; five to seven on the radius. Both medullary shells with regular, circular pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 4. Surface covered with thirty to fifty pyramidal main spines, as long as the diameter of the inner shell, and with numerous small conical by-spines of half the length.
Dimensions.—Diameter of the outer shell 0.11, middle 0.05, inner 0.025; cortical pores 0.01 to 0.02, bars 0.004; length of the main spines 0.03, basal breadth 0.005.
Habitat.—North Atlantic, Station 353, surface.
6. Echinomma trinacrium, Haeckel.
Actinomma trinacrium, Haeckel, 1862, Monogr. d. Radiol., p. 441, Taf. xxiv. figs. 6-8.
Cortical shell thin walled, with irregular, roundish pores, twice to three times as broad as the bars. Both medullary shells with regular, circular pores. Radial proportion of the three spheres = 1 : 3 : 9. On the surface about twenty three-sided pyramidal main spines, as long as the radius, and numerous (forty to sixty) by-spines of half the length. (Compare with this species Actinomma trinacrium, with which it is connected by transitional forms.)
Dimensions.—Diameter of the outer shell 0.09, middle 0.03, inner 0.01; cortical pores 0.008 to 0.012, bars 0.004; length of the spines 0.02 to 0.05, basal breadth 0.01.
Habitat.—Mediterranean (Messina).
7. Echinomma toxopneustes, n. sp. (Pl. [29], fig. 1).