The Perispyrida, the second subfamily, possess no free apophyses, but a three-jointed shell with two distinct transverse strictures, an upper mitral and a lower collar stricture. The network of this shell is incomplete in _Amphispyris_ (Pl. 88, figs. 2-7), being developed only in the frontal or lateral perimeter, thus making it probable that this subfamily may have arisen directly from the Tympanida (_Toxarium_, Pl. 88, fig. 1; Pl. 93, figs. 18-20). The network of _Tricolospyris_ (Pl. 88, figs. 8-11) is complete, of another shape in the cephalis than in the galea and thorax; it is doubled or spongy in _Perispyris_ (Pl. 88, figs. 12, 13). The Nephrospyrida, the third subfamily, contains two very different genera only, each of which may represent a separate family. _Sphærospyris_ (Pl. 83, fig. 4) possesses a spherical or subspherical lattice-shell, the central part of which includes a sagittal ring, connected with the inner face of the sphere by a number of paired apophyses, corresponding to those of _Lithocircus_; it may be easily confounded with some #Sphæroidea# (_Carposphæra_), but the enclosed ring leaves no doubt as to its true origin. _Nephrospyris_ (Pl. 90) has a flat discoidal shell of considerable size, usually kidney-shaped or cordate, with a deep sagittal incision at the base, indicating the region where the pseudopodia are protruded from the porochora. The violin-shaped central capsule has two large lateral lobes on each side of the including sagittal ring, and the transverse nucleus is perpendicular to its sagittal plane (Pl. 90, figs. 7, 10). _Sphærocircus_ as well as _Nephrospyris_ have probably arisen independently from the Stephanida. {1092}_Synopsis of the Genera of Androspyrida._ ------------------------------------------------------------------------- I. Subfamily Lamprospyrida. Three free basal feet. ------------------------------------------------------------------------- Lattice-work simple, not {Apical horn usually spongy. { simple, not { fenestrated, 479. _Androspyris_. Lattice-work wholly or {Apical horn usually partly spongy. { branched and { fenestrated, 480. _Lamprospyris_. ------------------------------------------------------------------------- II. Subfamily Perispyrida. No free basal feet. Shell three-jointed. ------------------------------------------------------------------------- {Lattice-work only { complete in the { frontal ring, 481. _Amphispyris_. Shell with two transverse { coronal strictures (one {Lattice-work complete superior mitral and one { on all sides, 482. _Tricolospyris_. inferior collar { stricture). {Lattice-work double { or spongy, 483. _Perispyris_.