2. Euscenium archicyrtis, n. sp.
Shell three-sided pyramidal, smooth, nearly as long as broad, with three straight edges connected by irregular loose framework with polygonal meshes. Basal plate with three very large simple collar-holes. The apical horn and the three feet are three-sided prismatic, smooth, about twice as long as the columella, straight and widely divergent.
Dimensions.—Shell 0.08 long, 0.1 broad.
Habitat.—Tropical Pacific, Station 225, depth 4475 fathoms.
3. Euscenium hemisphæricum, n. sp.
Shell hemispherical smooth, half as long as broad, with small and numerous subregular circular pores. Basal plate with three large triangular simple collar-holes. Horn slender, three-sided prismatic, twice as long as the columella. Feet very slender, with three denticulate edges, widely divergent and curved like the quadrant of a circle.
Dimensions.—Shell 0.04 long, 0.06 broad.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
4. Euscenium tricolpium, n. sp. (Pl. [53], fig. 12).
Archiscenium tricolpium, Haeckel, 1881, Prodromus et Atlas, loc. cit.