3. Spongoprunum amphicylindrus, n. sp.
Shell nearly cylindrical, four times as long as broad, with rough surface. Spongy framework compact, in the whole shell of equal structure, with small meshes, twice to three times as broad as the bars. Two polar spines cylindrical, very large, longer than the shell, and about one-fourth as thick as its diameter.
Dimensions.—Length of the shell 0.2, breadth 0.05.
Habitat.—South Atlantic, Station 333, surface.
Subfamily Spongodruppida, Haeckel.
Definition.—Spongurida with latticed medullary shell, enclosed by a spongy cortical shell.
Genus 148. Spongodruppa,[[187]] n. gen.
Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a simple, spherical or ellipsoidal, latticed medullary shell. Polar spines absent.
The genus Spongodruppa opens the series of Spongodruppida, or of those Spongurida in which the ellipsoidal spongy cortical shell encloses a simple or double, latticed, medullary shell. In Spongodruppa, the simplest and probably the ancestral form of this subfamily, the medullary shell is simple and the polar spines absent. It may be derived from Druppula by a spongy thickening of the simple latticed cortical shell.