Definition.—Sphærozoida with simple needle-shaped spicula, which are neither radiate nor branched.

The genus Belonozoum comprises the Sphærozoida with simple needle-shaped spicula, and may be regarded as the colonial form of Thalassosphæra or Thalassoplancta, derived from these solitary Beloidea by multiplication of the capsules and union in a common calymma.

1. Belonozoum bacillosum, n. sp.

Sphærozoum bacillosum, Haeckel, 1881, Manuscript.

Spicula all simple rods, straight cylindrical, obtuse at both ends, quite smooth. Central capsule pellucid, with one single central oil-globule.

Dimensions.—Diameter of the central capsule 0.08 to 0.12, length of the spicula 0.05 to 0.08.

Habitat.—Central Pacific, Station 271, surface.

2. Belonozoum spinulosum, Haeckel.

Sphærozoum spinulosum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 54, Taf. viii. fig. 4.

Sphærozoum spinulosum, Haeckel, 1862, Monogr. d. Radiol., p. 527, Taf. xxxiii. figs. 3, 4.