Page:Scientific results HMS Challenger vol 18 part 1.djvu/250

42 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.

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.

6. Sphærozoum furculosum, 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 curved or bent, pointed, thorny, with many small spinules, commonly somewhat shorter than the middle rod.

Dimensions.—Diameter of the central capsules 0.2 to 0.25, length of the axial rod of the spicula 0.1, of its shanks 0.05 to 0.08.

Habitat.—South Atlantic, near Tristan da Cunha, Station 334, surface.

7. Sphærozoum ovodimare, Haeckel.

Sphærozoum ovodimare, Haeckel, 1862, Monogr. d. Radiol., p. 527, Taf. xxxiii. figs. 5, 6.

Sphærozoum punctatum, var., Brandt, 1881, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, Taf. i. fig. 54.

Spicula all (or nearly all) geminate and triradiate, composed of a long simple axial rod and three simple needle-like shanks on each end of it. Shanks straight, pointed, smooth, commonly shorter than the middle rod. (Often few furcate or four-rayed spicula are intermixed, or few spicula are not smooth, but thorny.)

Dimensions.—Diameter of the central capsules 0.05 to 0.2, length of the middle rod of the spicula 0.02 to 0.06, of its shanks 0.01 to 0.04.

Habitat.—Mediterranean, Naples, Messina, Haeckel; Atlantic, Canary Islands, Cape Verde Islands, West Coast of Africa, Stations 351 to 354; surface.