Page:Scientific results HMS Challenger vol 18 part 1.djvu/577

Rh Dimensions.—Main axis of the outer cortical shell 0.3, of the middle 0.22, of the inner 0.15; greatest breadth of the inner cortical shell 0.1, its pores 0.01, bars 0.005.

Habitat.—Indian Ocean, Madagascar, Rabbe, surface.

2. Cyphocolpus virginis, n. sp. (Pl. 40, fig. 11).

Zygartus virginis, Haeckel, 1881, Prodromus et Atlas (pl. xl. fig. 11).

Inner cortical shell with irregular, roundish pores, twice to three times as broad as the bars; eleven to twelve on the half meridian of each chamber, sixteen to eighteen on its half equator. Middle cortical shell with very delicate network, its irregular, polygonal pores of the same size as those of the inner, but separated by extremely thin bars. Outer cortical shell with spiny surface, and with more irregular, roundish pores of different size. The distance between each two shells is variable, and attains more than the diameter of the outer medullary shell, which, like the inner, is spheroidal, slightly compressed.

Dimensions.—Main axis of the outer cortical shell 0.26, of the middle 0.22, of the inner 0.14; greatest breadth of the inner cortical shell 0.09, its pores 0.004 to 0.006, bars 0.002.

Habitat.—Pacific, central area, Station 271, surface.

Definition.— with simple cortical shell and simple medullary shell, with two opposite polar spines (or bunches of polar spines) on the poles of the main axis.

The genus Cyphinus differs from Cyphanta by the development of two opposite spines (or bunches of spines) on both poles of the main axis. It simulates therefore the bipolar formation of Stylartus, and differs from this in the possession of a medullary shell.

Definition.—On both poles of the main axis only one single large spine.

1. Cyphinus amphacanthus, n. sp.

Cortical shell with smooth surface, and circular, regular pores, twice as broad as the bars; five to six pores on the half meridian of each chamber, ten to twelve on its half equator. On both poles of the main axis, one single, very strong, conical spine, about half as long as this axis, and half as broad at the base as the spherical medullary shell.

Dimensions.—Main axis of the cortical shell (without spines) 0.2, greatest breadth (in the equator of each chamber) 0.1; pores 0.006, bars 0.003; length of the polar spines 0.1, basal thickness of them 0.02.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.