The genus Sphærospyris differs from all other Spyroidea in the regular spherical or spheroidal form of the lattice-shell. It may therefore be easily confounded with some species of the Sphæroidea; but the internal sagittal ring, placed in the median plane of the fenestrated sphere and connected with it by radial beams, leaves no doubt that it is derived from a true Spyroid, either Dictyospyris or Amphispyris, or another genus. Sometimes also four larger collar pores are visible.
1. Sphærospyris sphæra, Haeckel.
Dictyospyris sphæra, Bütschli, 1882, Zeitschr. f. wiss. Zool. vol. xxxvi. pp. 511, 539, Taf. xxxii. fig. 15, a, b.
Shell smooth, nearly spherical, slightly flattened at the base, with small regular circular pores. In the centre of the basal plate a regular rectangular cross with four equal collar pores.
Dimensions.—Diameter of the shell 0.11, of the enclosed ring 0.06.
Habitat.—Fossil in Barbados.
2. Sphærospyris quadriforis, n. sp.
Shell rough, nearly spherical, slightly flattened at the base, with small regular circular pores. In the centre of the basal plate a bilateral symmetrical cross with four ovate collar pores; two cardinal pores twice as large as the two jugular pores and six to eight times as broad as the other shell-pores.
Dimensions.—Diameter of the shell 0.26, of the enclosed ring 0.09.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.