Cortical shell one and a third times as long as broad, armed with numerous thin, bristle-shaped, radial spines, nearly as long as the shell. Spongy framework loose, with large meshes, its thickness nearly equal to the diameter of the outer spherical medullary shell.
Dimensions.—Length of the cortical shell 0.18, breadth 0.14; thickness of its wall 0.035; diameter of the outer medullary shell 0.04, of the inner 0.02.
Habitat.—South Atlantic, Station 325, surface.
6. Spongoliva daturina, n. sp.
Cortical shell one and a half times as long as broad, armed with numerous, thick and short, conical radial spines, about as long as the outer medullary shell. Spongy framework compact, with small meshes, its thickness equal to half the length of the outer ellipsoidal medullary shell.
Dimensions.—Length of the cortical shell 0.24, breadth 0.16; thickness of its wall 0.025; diameter of the outer medullary shell 0.045 to 0.035, of the inner 0.025.
Habitat.—Pacific, central area, Station 272, surface.
Genus 151. Spongoxiphus,[[190]] n. gen.
Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a double, spherical or ellipsoidal, latticed medullary shell. On the poles of the axis occur two opposite strong spines.
The genus Spongoxiphus differs from Spongoliva by the development of two strong spines in the axis of the shell, on its two opposite poles. From the similar Spongatractus it differs in the duplication of the medullary shell. It may also be regarded as a Stylatractus, in which the simple latticed cortical shell is replaced by an irregular spongy framework.