4. Sphærozoum hexactinium, n. sp.
Spicula all (or nearly all) hexaradiate, composed of six (or sometimes in few spicula five or seven) needle-like shanks, mostly of equal size, diverging from one common point in two opposite hemispheres (three needles upwards, three needles downwards). Shanks somewhat curved, pointed, smooth. Central capsules spherical, small, with one central oil-globule. This species may be regarded as the social form of Thalassoxanthium hexactinium.
Dimensions.—Diameter of the central capsule 0.06 to 0.08, length of the spicula-shanks 0.05 to 0.06.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray.
Subgenus 2. Sphærozonoceras, Haeckel.
Definition.—Spicula all geminate-radiate, consisting of one middle rod, which bears an equal and constant number of rays (two, three, or four) at each end.
5. Sphærozoum furcatum, n. sp.
Spicula all (or nearly all) geminate and simply forked, composed of a simple axial rod and two simple needle-like shanks on each end of it. Shanks straight, pointed, smooth, commonly somewhat longer than the middle rod.
Dimensions.—Diameter of the central capsules 0.1 to 0.15, length of the axial rod of the spicula 0.03, of its shanks 0.04 to 0.06.
Habitat.—Tropical zone of the Atlantic, near Ascension Island, Station 344, surface.