Page:Scientific results HMS Challenger vol 18 part 1.djvu/358

150 2. Spongostylus gladiatus, Haeckel.

Stylosphæra holosphæra, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 299, Taf. viii. fig. 14.

Spongy cortical shell with rather compact framework, four times as broad as the enclosed medullary shell, the pores of which are irregular, roundish, three to four times as broad as the bars. Two polar spines sword-shaped, two-edged, as long as the shell diameter.

Dimensions.—Diameter of the cortical shell 0.24, medullary shell 0.06; length of the spines 0.25.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms; Philippine Sea, depth 3300 fathoms.

3. Spongostylus serratus, n. sp.

Spongy cortical shell with lax framework, ten to twelve times as broad as the enclosed medullary shell, the pores of which are irregular, roundish, once and a half to twice as broad as the bars. Two polar spines longer than the shell diameter (broken off in the observed specimen), three-sided prismatical, with three straight serrated edges.

Dimensions.—Diameter of the cortical shell 0.5, medullary shell 0.04; length of the spines 0.6 or more.

Habitat.—South Pacific, Station 285, depth 2375 fathoms.

Definition.— with spongy spherical cortical shell, enclosing two concentric spherical latticed medullary shells, and with two opposite, free radial spines.

The genus Spongostylidium differs from Spongostylus by duplication of the latticed medullary shell, and therefore bears the same relation to it as Spongodictyon to Spongoplegma.

1. Spongostylidium streptacanthum, n. sp.

Both medullary shells spherical, with small, regular, circular pores, twice as broad as the bars (outer twice as broad as the inner). Spongy cortical shell enclosing it with dense framework, four times as broad as the outer medullary shell. Two polar spines very large, four times as long as the diameter of the outer shell; as broad as the inner medullary shell, with three dentated, spirally contorted edges. (Very similar to the common Spongosphæra streptacantha and to Hexadoridium streptacanthum, but with only two opposite spines in one axis.)

Dimensions.—Diameter of the cortical shell 0.16, of the outer medullary shell 0.04, inner 0.02; length of the spines 0.7 and more, breadth 0.02.

Habitat.—Indian Ocean, Cocos Islands, Rabbe.