Page:Scientific results HMS Challenger vol 18 part 1.djvu/241

Rh 5. Thalassoxanthium cervicorne, n. sp. (Pl. 2, figs. 3, 4).

Spicula all triradiate, trichotomously branched, with three equal shanks, which diverge from one common point, and are again provided each with three branches on the distal end. These nine branches are commonly once or twice forked (each fork rarely provided with three ramules). The ramules are thin, unequal, curved, or bent, and the ramification nearly resembles a stag's horn. Central capsule transparent, without oil-globules, two to three times as broad as the dark nucleus, which contains one single long central nucleolus. Calymma thin, scarcely as thick as the radius of the nucleus.

Dimensions.—Diameter of the central capsule 0.2 to 0.25, of the nucleus 0.08 to 0.1, length of the spicula 0.05 to 0.15.

Habitat.—Central Pacific, Stations 271, 274, surface.

Definition.—Spicula all or partly geminate, consisting of one middle or axial rod, from the two poles of which diverge two, three, or more shanks in different directions. Shanks or needle-rays sometimes simple, needle-like, sometimes bifurcated or branched.

6. Thalassoxanthium 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, somewhat shorter than the middle rod. Central capsule yellowish, dark, three times as broad as its central dark nucleus; besides this a single oil-globule, nearly of the same size.

Dimensions.—Diameter of the central capsule 0.1, of its nucleus 0.03; length of the axial rod of the spicula 0.04, of its shanks 0.03.

Habitat.—Cape Verde Islands.

7. Thalassoxanthium bifurcum, Haeckel.

Thalassosphæra bifurca, Haeckel, 1862, Monogr. d. Radiol., p. 260, Taf. xii. fig. 1.

Sphærozoum bifurcum, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 845.

Spicula all geminate and double forked, composed of a simple axial rod and two forked branches on each end; these branches are again forked, so that each spiculum exhibits eight thin distal ends. All branches are thin, slender and straight. Central capsule red, four times as broad as the central nucleus, containing between the red pigment-granules numerous, peculiar, violin-shaped bodies (fat-corpuscles?). Compare fig. 1, ''loc. cit.''

Dimensions.—Diameter of the central capsule 0.08, of the nucleus 0.02, length of the spicula 0.05 to 0.08.

Habitat.—Mediterranean (Messina), surface, Haeckel.