_Dimensions._--Shell 0.12 long, 0.08 broad; ring 0.04 long. _Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. 2. _Tricolospyris leibnitziana_, n. sp. (Pl. 88, fig. 9). Shell spiny, twice as long as broad, with two deep transverse strictures. Pores of the cephalis large, roundish, polygonally framed, of very different size; two middle transverse rows of smaller pores enclosed between a superior and an inferior row of very large pores. Cupola and thorax hemispherical, about equal, with much smaller and very numerous roundish pores. _Dimensions._--Shell 0.15 long, 0.07 broad; ring 0.06 long. _Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. 3. _Tricolospyris baconiana_, n. sp. (Pl. 88, fig. 8). Shell rough, twice as long as broad, with two sharp strictures. Pores of the cephalis large, very irregular, partly lobated. Cupola hemispherical, smaller than the campanulate thorax, both with smaller irregular pores. _Dimensions._--Shell 0.15 long, 0.08 broad; ring 0.06 long. _Habitat._--Western Tropical Pacific, Station 215, depth 2500 fathoms. 4. _Tricolospyris newtoniana_, n. sp. (Pl. 88, fig. 11). Shell spiny, slender, three times as long as broad, with two distinct strictures. Pores of the cephalis very large, irregular. Cupola hemispherical, only one-third as long as the slender inversely conical abdomen, both with irregular, much smaller pores. _Dimensions._--Shell 0.22 long, 0.08 broad; ring 0.05 long. _Habitat._--Western Tropical Pacific, Station 206, depth 2100 fathoms. Genus 483. _Perispyris_,[101] Haeckel, 1881, Prodromus, p. 444. _Definition._--#Androspyrida# without free basal feet, with three distinct joints, separated by two transverse strictures; lattice-work of the shell double or spongy. The genus _Perispyris_ differs from the preceding _Tricolospyris_, its ancestral form, in the development of a secondary outer shell, which encloses the inner primary one either like an enveloping cortical shell or like a spongy veil. This is produced by the concrescence of meeting branches, which arise from spines of the inner shell. {1099}1. _Perispyris bicincta_, n. sp. (Pl. 88, fig. 13). Shell smooth, with two deep transverse annular strictures and a deep sagittal incision at the sternal base; one and a half times as long as broad. Cephalis nut-shaped, with large irregular roundish pores and very broad bars. Everywhere from its surface there arise numerous slender arborescent radial beams; by the anastomoses of their ramified branches there arise the flat cap-shaped cupola and the larger bilobed thorax; and also the external enveloping shell with loose delicate network. _Dimensions._--Inner shell 0.17 long, 0.1 broad; outer shell 0.23 long, 0.17 broad; ring 0.06 long. _Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. 2. _Perispyris spongiosa_, n. sp.