Terminal branches regularly forked, with two equal, smooth, nearly straight or slightly curved fork-branches, diverging at right angles; their end-knobs with four crossed (or sometimes five or six) short recurved teeth.
Dimensions.—Diameter of the spherical skeleton 1.2 to 1.8, of the two central valves 0.2 to 0.25.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; many Stations, surface and at various depths.
2. Cœlodendrum spinosissimum, n. sp. (Pl. [121], fig. 7).
Terminal branches regularly forked, with two equal, smooth, straight, fork-branches, diverging at right angles, their end-knobs echinoidal, subspherical or club-shaped, with numerous short radial thorns.
Dimensions.—Diameter of the skeleton 2 to 2.2, of the two central valves 0.25 to 0.03.
Habitat.—Tropical Atlantic, Stations 346 to 349, surface.
3. Cœlodendrum furcatissimum, n. sp. (Pl. [121], fig. 1-4).
Terminal branches regularly forked, with two equal, smooth, straight, or slightly curved fork-branches, diverging at acute angles; their end-knobs very small, with three short, diverging, conical teeth.
Dimensions.—Diameter of the skeleton 2 to 2.5, of the two central valves 0.3 to 0.4.