Habitat.—South Pacific, Station 295, depth 1500 fathoms.
2. Staurotholonium bicruciatum, n. sp.
Outer cortical shell rough, twice as large as the inner, of the same form and structure, at an equal distance from it. In both shells the principal cupolas are larger than the lateral. Pores irregular, roundish, in the outer shell four times, in the inner twice as large as the bars; eight to ten in the basal semicircle of one cupola. (Similar to Staurotholus cruciatus, but differs mainly in the double cortical shell.) Medullary shell lentelliptical.
Dimensions.—Major (longitudinal) axis of the outer cortical shell 0.016, of the inner 0.08; minor (transverse) axis of the former 0.14, of the latter 0.07; medullary shell 0.03 to 0.04.
Habitat.—Pacific, central area, Station 267, depth 2700 fathoms.
3. Staurotholonium alternatum, n. sp.
Outer cortical shell smooth, very different from the inner; in the outer the two principal cupolas are larger than the two lateral; in the inner inversely smaller. Pores subregular, circular, in the outer shell four times, in the inner shell twice as broad as the bars; ten to twelve pores in the basal semicircle of one cupola.
Dimensions.—Major axis (length) of the outer cortical shell 0.15, minor (breadth) 0.13; pores 0.012, bars 0.003; major axis (length) of the inner cortical shell 0.11, minor axis (breadth) 0.09; pores 0.006, bars 0.003.
Habitat.—Indian Ocean, surface, Madagascar, Rabbe.
4. Staurotholonium lenticulare, n. sp.