Definition.—Apophyses of the spines simple, not branched; therefore each spine with four sutural condyles.
1. Stauraspis cruciata, n. sp. (Pl. [134], fig. 5).
Radial spines thin, quadrangular, prismatic; outer and inner half nearly of equal length. Central bases pyramidal, with wing-like edges. Four apophyses of each spine simple, not branched, with thin condyles. Large meshes of the shell ten to twenty times as broad as the bars. This and the following species greatly resemble the simplest forms of Phractaspis (Pl. [137], figs. 1, 2); they differ from these, however, by the equal size and distance of the four branches of each spine, which thus form a rectangular cross.
Dimensions.—Diameter of the shell 0.1; breadth of the spines and bars 0.002.
Habitat.—Central Pacific, Station 268, surface.
2. Stauraspis xiphacantha, n. sp.
Radial spines stout, cylindrical in the inner half, conical in the shorter outer half. Four apophyses of each spine simple, not branched, broad, with thick condyles. Meshes of the shell six to eight times as broad as the bars.
Dimensions.—Diameter of the shell 0.12; breadth of the spines and bars 0.008 to 0.01.
Habitat.—South Pacific, Station 290, surface.