Page:Scientific results HMS Challenger vol 18 part 1.djvu/509

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Definition.—Network of the shell irregular, with pores of different size or form.

7. Ellipsostylus megadictya, Haeckel.

Stylosphæra megadictya, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 299, Taf. viii. fig. 13.

Proportion of the major axis to the minor = 5 : 4. Shell thin walled, with irregular, roundish, large meshes, four to five times as broad as the bars; only four to five on the half equator. Surface smooth. Polar spines straight, thin, angular; the shorter equal to the minor axis, the longer four times as large.

Dimensions.—Longer axis 0.05, shorter axis 0.04; meshes 0.01, bars 0.002; length of the polar spines—longer 0.12, shorter 0.03.

Habitat.—Philippine Sea, 3300 fathoms, Ehrenberg.

8. Ellipsostylus gallinula, n. sp.

Proportion of the major axis to the minor = 3 : 2. Shell thick walled, with irregular, roundish meshes, twice to four times as broad as the bars; eight to ten on the half equator. Surface thorny. Polar spines conical, straight; the longer twice as long as the major axis, the minor scarcely half as long.

Dimensions.—Longer axis 0.15, shorter 0.12; pores 0.01 to 0.02, bars 0.002 to 0.004.

Habitat.—North Pacific, Station 253, surface.

9. Ellipsostylus hirundo, n. sp. (Pl. 13, fig. 2).

Proportion of the major axis to the minor = 4 : 3. Shell thick walled, with irregular, roundish meshes, three to five times as broad as the bars; eight to ten on the half equator. The inner aperture of every mesh is fenestrated by a delicate lamella of silex, perforated by six to eight very small circular pores. Polar spines sharp edged, more or less curved, the shorter equal to the minor axis, the longer twice as long.

Dimensions.—Longer axis 0.16, shorter 0.12; pores 0.01 to 0.02, bars 0.003 to 0.006; length of the polar spines—longer 0.24, shorter 0.12.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms; the same form also fossil in the rocks of Barbados.

Definition.— with simple ellipsoidal or oviform shell, the main axis of which bears at one pole a single spine, at the other a bunch of several spines.