Page:Scientific results HMS Challenger vol 18 part 1.djvu/519

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Definition.— with simple ellipsoidal cortical shell and simple medullary shell, with numerous radial spines, without polar tubes.

The genus Druppocarpus differs from Druppula only in the radial spines, which arise between the pores of the cortical shell, and therefore exhibits the same relation to it that Ellipsidium bears to Cenellipsis, or Prunocarpus to Prunulum.

Definition.—Network of the cortical shell regular, with meshes of equal size and similar form.

1. Druppocarpus ananassa, n. sp.

Cortical shell thin walled, with regular, circular, hexagonally framed pores, of about the same breadth as the elevated bars; fourteen to sixteen on the half equator. From each hexagon-corner (between every three pores) arises a short thin radial spine, about as long as two pores, three-sided pyramidal at the base. Proportion of both cortical axes = 4 : 3. Medullary shell spherical, half as broad as the cortical shell. (Greatly resembles Druppula pandanus, Pl. 39, fig. 3, but differs in the larger medullary shell and the spines on the surface.)

Dimensions.—Major axis of the ellipsoidal cortical shell 0.16, minor 0.12; pores and bars 0.006; length of the radial spines 0.02; diameter of the medullary shell 0.06.

Habitat.—South Pacific, Station 289, surface.

2. Druppocarpus castanea, n. sp.

Cortical shell thin walled, with regular circular pores (without hexagonal frames), of about the same breadth as the bars; twelve to fourteen on the half equator. Between every three meshes arise a short conical spine with bristle-like apex, twice to four times as long as one pore. Proportion of both cortical axes = 3 : 2. Medullary shell spherical, one-third as broad as the cortical. (Resembles very closely the spherical Haliomma castanea, Haeckel, figured in my Monograph. pl. xxiv. fig. 4.)

Dimensions.—Major axis 0.15, minor axis 0.1; pores and bars 0.005; length of the radial spines 0.01 to 0.02; medullary shell 0.035.

Habitat.—North Atlantic, surface; Canary Islands, Lanzerote, Haeckel.

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