Shell rough, with two distinct transverse strictures and a deep sternal incision, similar to the preceding; the radial beams arising from the inner shell, and forming by anastomosing branches the outer shell, are thinner and more numerous, and the framework of the latter on the surface is very dense and spongy, therefore the shell is dark and not transparent. _Dimensions._--Inner shell 0.18 long, 0.12 broad; outer shell 0.24 long, 0.18 broad; ring 0.08 long. _Habitat._--Central Pacific, Station 265, depth 2900 fathoms. 3. _Perispyris lentellipsis_, n. sp. (Pl. 88, fig. 12). Shell smooth, lentelliptical, with three different isopolar axes, perpendicular one to another. Transverse and sagittal strictures are wanting; but the large enclosed ring and the two pairs of large adjacent annular meshes indicate clearly the position and size of the hidden cephalis. The two other joints (the cupola on the upper and the thorax on the lower pole of the cephalis) are nearly equal, cap-shaped or hemispherical. The outer lentelliptical shell is little larger than the inner, connected with it by numerous thin bristle-shaped radial beams, and exhibits a delicate arachnoidal lattice-work. _Dimensions._--Inner shell 0.15 long, 0.1 broad; outer shell 0.18 long, 0.13 broad; ring 0.08 long. _Habitat._--Central Pacific, Station 272, depth 2600 fathoms. Subfamily 3. NEPHROSPYRIDA (vel PARADICTYIDA, Haeckel, 1881). _Definition._--#Androspyrida# without free basal feet and external constrictions. Shell either spherical or discoidal. Genus 484. _Sphærospyris_,[102] n. gen. _Definition._--#Androspyrida# with a spherical or subspherical shell, without basal incision and transverse constriction; without free basal feet. {1100}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.