Sphærozoum bicellulare, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 54, Taf. viii. fig. 5.
Thalassicolla punctata, Huxley (pro parte), 1851, Ann. and Mag. Nat. Hist., ser. 2, vol. viii. p. 433.
Central capsules spherical, with thin, simple-edged membrane, with one single oil-globule in the centre. (If the capsules multiply by division, the spherical form becomes violin-shaped, constricted in the middle; and in this condition the number of oil-globules increases; but in the ordinary mature state the capsule of this species remains spherical, and its oil-globule solitary. In quite young capsules the oil-globules are wanting; Pl. [3], fig. 12.)
Dimensions.—Diameter of the central capsules 0.04 to 0.16.
Habitat.—Cosmopolitan, common in all warmer seas (Mediterranean, Atlantic, Indian, and Pacific), surface.
2. Collozoum nostochinum, n. sp.
Central capsules spherical, very large, opaque, distended with red pigment-granules and with very numerous (two hundred to three hundred) small oil-globules. Membrane thick, double-edged.
Dimensions.—Diameter of the central capsules 0.3 to 0.5.
Habitat.—Indian Ocean, off Socotra, surface, Haeckel.
3. Collozoum volvocinum, n. sp.