Page:Scientific results HMS Challenger vol 18 part 1.djvu/307

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Definition.— with simple shells, having on the inside radial centripetal tubes, the walls of which are fenestrated.

The genus Buccinosphæra exhibits, on the inner surface of the shell, radial centripetal tubules similar to those of the foregoing Pharyngosphæra; but the walls of these tubes are here latticed, not solid; they represent therefore true invaginations of the whole shell-wall.

1. Buccinosphæra invaginata, n. sp. (Pl. 5, fig. 11).

Shell irregular roundish or nearly polyhedral, with a variable number of umbilical depressions, which are prolonged on the inside into cylindrical or somewhat conical, centripetal, fenestrated tubes, about one-third as long as the shell radius. Inner mouth of the tubes narrower, scarcely half as broad as the outer mouth, about equal to one-fourth the shell radius, truncated. Pores of the tubes and of the shell small, roundish, irregular in size and distribution, about as broad as the bars. Twenty-five to thirty pores in the half meridian of the shell. In all observed specimens the spherical central capsule (half as broad as the shell) contained a large number of crystals.

Dimensions.—Diameter of the shell 0.1 to 0.12, of the pores 0.001 to 0.003, of the bars 0.002 to 0.003; length of the tubuli 0.02; outer mouth 0.026, inner mouth 0.013; crystals in the central capsule 0.002 to 0.004, sometimes 0.008.

Habitat.—Philippine Islands (Samboangan), Station 213, surface.

2. Buccinosphæra tubaria, n. sp.

Shell irregular polyhedral with rounded edges, with a variable number of umbilical depressions, which are prolonged on the inside into large, nearly cylindrical, centripetal, fenestrated tubes, half as long as the shell radius. In the middle the tubes are somewhat constricted and narrower. Inner mouth of the tubes dilated, nearly as broad as the outer mouth, about equal to one-half the shell-radius, truncated. Pores of the tubes and of the shell large, roundish polygonal, irregular in size and distribution, three to four times as broad as the bars. Fifteen to twenty pores in the half meridian of the shell.

Dimensions.—Diameter of the shell 0.12 to 0.14, of the pores 0.008 to 0.012, of the bars 0.002 to 0.004; length of the tubuli 0.03; outer mouth 0.04, inner mouth 0.03.

Habitat.—North coast of New Guinea, Station 217, surface.

Definition.— with simple shells, the outer surface of which is covered with radial, irregularly scattered spines.