6. Acrosphæra inflata, n. sp. (Pl. [5], fig. 7).
Mazosphæra inflata, Haeckel, 1879, Atlas, loc. cit.
Shell more or less irregular, polyhedral, hilly, with a variable number (six to twelve) of large pyramidal, hill-like prominences; every hill about as high as broad, on the top a strong conical, radial, or obliquely inserted spine, inflated, with three to six very large polygonal meshes, much larger than the other pores between the hills, which are also polygonal, two to six times as broad as the bars. Ten to fifteen pores on the half meridian.
Dimensions.—Diameter of the shell 0.1 to 0.14, of the largest pores 0.05, of the smallest 0.005; length of the spines 0.02 to 0.03.
Habitat.—North Atlantic, Station 64, surface.
Genus 34. Odontosphæra,[[56]] n. gen.
Definition.—Collosphærida with simple shells, the outside of which bears single scattered spines, one single spine on the margin of each larger pore.
The genus Odontosphæra is distinguished from the foregoing Acrosphæra by the peculiar disposition of the spines, which are not scattered on the outside of the shell between the pores, but so disposed that each larger pore is protected by one single spine, obliquely placed over it.
1. Odontosphæra monodon, n. sp. (Pl. [5], fig. 5).
Shell spherical or subspherical, with very small and numerous circular pores, much smaller than the bars. Twelve to fifteen pores on the half meridian of the shell. Between them a variable number of larger roundish apertures (mostly twelve to sixteen) irregularly scattered, one-fourth to one-fifth as broad as the shell radius. On the margin of every larger aperture a single (rarely two or three) sharp conical tooth, about as long as the diameter of the aperture, and obliquely laid over them.