{1144}4. _Tripodiscium campanula_, Haeckel. _Carpocanium campanula_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 96, Taf. iii. fig. 9. Shell campanulate or subspherical, smooth, about as long as broad. Pores small, regular circular, as broad as the bars. Mouth constricted, about half as broad as the shell, with three short conical descending feet. _Dimensions._--Shell 0.06 long, 0.05 broad; feet 0.02 long. _Habitat._--North Pacific, Station 244, depth 2900 fathoms; fossil in Sicily. Subgenus 2. _Tripodisculus_, Haeckel. _Definition._--Feet branched or forked. 5. _Tripodiscium furcatum_, n. sp. Shell ovate, rough, nearly as broad as long. Pores subregular, circular, twice as broad as the bars. Mouth constricted, two-thirds as broad as the shell, with three divergent parallel and vertical feet, which are as long as the shell, and forked at the distal end. _Dimensions._--Shell 0.09 long, 0.08 broad; feet 0.07 long. _Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. 6. _Tripodiscium ramosum_, n. sp. Shell ovate, tuberculate, nearly as broad as long. Pores irregular, roundish, of very different sizes. Mouth constricted, half as broad as the shell, with three large, divergent, irregularly branched feet, nearly twice as long as the shell. (Similar to _Tristylospyris ramosa_, Pl. 52, fig. 23, but without sagittal ring and constriction.) _Dimensions._--Shell 0.07 long, 0.06 broad; feet 0.15 long. _Habitat._--Central Pacific, Station 274, depth 2750 fathoms. 7. _Tripodiscium sphærocephalum_, n. sp. (Pl. 52, fig. 21). Shell subspherical, rough, with circular pores of different sizes. Mouth constricted, circular, simple, two-thirds as broad as the shell, with three large divergent feet, which are three-sided prismatic, irregularly branched, and twice as long as the shell. _Dimensions._--Shell 0.07 long, 0.08 broad; feet 0.12 long. _Habitat._--Central Pacific, Station 272, depth 2600 fathoms. {1145}Genus 503. _Tridictyopus_,[120] Haeckel, 1881, Prodromus, p. 428. _Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three latticed terminal feet. Shell ovate or subconical, with an apical horn. The genus _Tridictyopus_ differs from the nearly allied _Tripilidium_ in the possession of three large fenestrated shovel-shaped feet, forming direct prolongations of the large conical shell. The lattice work exhibits a peculiar elegant structure recurring in the similar, perhaps nearly related, _Cephalospyris_ (Pl. 83, fig. 10; Pl. 96, fig. 28). The central capsule is large, ellipsoidal or ovate, and fills up the greater part of the shell cavity (compare R. Hertwig, 1879, _loc. cit._, p. 75). 1. _Tridictyopus vatillum_, n. sp. (Pl. 51, fig. 8). Shell campanulate, about as long as broad (excluding horn and feet). Pores irregular, polygonal, in the middle part more regular, triangular. Horn short and stout, three-sided pyramidal. Three feet large, triangular, shovel-shaped, about half as long as the shell.