Page:Scientific results HMS Challenger vol 18 part 1.djvu/516

308 from Carposphæra by prolongation of one axis, or from Cenellipsis by duplication of the fenestrated shell. The outer (or cortical) shell is always more or less ellipsoidal; the inner (or medullary) shell also is sometimes ellipsoidal, sometimes spherical. Both shells are concentric, connected by a variable number of radial beams. Compare Haliomma oblongum, Harting, 1863, L. N. 18, p. 15, pl. 2, fig. 42.

Definition.—Pores of the cortical shell regular, hexagonal, or circular.

1. Druppula drupa, n. sp.

Cortical shell thin walled, with smooth surface and regular network; both its axes bear the proportion of 4 : 3. Pores regular, hexagonal, three times as broad as the bars; twelve to fifteen on the half equator. Medullary shell spherical, about one-third as broad as the cortical shell.

Dimensions.—Major axis of the ellipsoidal cortical shell 0.1 to 0.12, minor axis 0.08 to 0.09; pores 0.06, bars 0.02; diameter of the medullary shell 0.03.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms; also fossil in Barbados.

2. Druppula pandanus, n. sp. (Pl. 39, fig. 3).

Cortical shell thin walled, somewhat rough, with regular network; both its axes bear the proportion of 3 : 2. Pores subregular, circular, hexagonally framed, one and a half times as broad as the elevated bars; ten to twelve on the half equator. Medullary shell spherical, one-fourth as broad as the cortical shell.

Dimensions.—Major axis of the cortical shell 0.16 to 0.17, minor axis 0.11 to 0.12; pores 0.01, bars 0.007; diameter of the medullary shell 0.035.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

3. Druppula cocos, n. sp.

Cortical shell thick walled, somewhat rough, with regular network; proportion of both axes = 6 : 5. Pores regular, circular, hexagonally framed, quite as broad as the elevated bars; fourteen to sixteen on the half equator. Medullary shell ellipsoidal (with longitudinal main axis), nearly half as large as the cortical shell.

Dimensions.—Major axis of the cortical shell 0.07 to 0.08, minor axis 0.6 to 0.65; pores and bars 0.003 to 0.004; diameter of the medullary shell 0.03 and 0.035.

Habitat.—Western Tropical Pacific, Station 222, surface, Indian Ocean, Ceylon, Haeckel.

4. Druppula phœnix, n. sp.

Cortical shell thick walled, smooth, with regular network; proportion of both axes = 5 : 4. Pores regular, circular, hexagonally lobulate (in the same manner as in Stauroxiphus gladius,