Shell cap-shaped, nearly hemispherical, with three vaulted hemispherical bosoms between the three arches ascending from the feet to the horn. Network very irregular, with polygonal meshes, of different form and size. Basal plate with three large primary and some smaller irregular accessory collar-holes. Horn slender, straight, twice as long as the columella. Feet of the same length, slender, widely divergent, slightly curved. The three edges of the horn and the feet are elegantly denticulated.
Dimensions.—Shell 0.04 long, 0.08 broad.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
5. Euscenium tripospyris, n. sp. (Pl. [84], fig. 8).
Tripospyris euscenium, Haeckel, 1881, Prodromus et Atlas.
Shell nearly spherical, smooth, with numerous small circular pores. Basal plate also with numerous small pores. Horn and feet stout, three-sided prismatic, straight or slightly curved, about as long as the thin, somewhat curved columella. This species is closely allied to Tripospyris.
Dimensions.—Shell 0.11 to 0.12 diameter, horn and feet 0.08 to 0.1 long.
Habitat.—South Pacific, Station 298, depth 2225 fathoms.
Subgenus 2. Euscenidium, Haeckel.
Definition.—Feet forked or branched.