Shell campanulate, smooth, with irregular polygonal pores, very similar to the preceding species but with much broader wings, forming several arcades with three to five rows of irregular meshes. Columella with five or six triradiate verticils of lateral branches. Horn twice as long as the shell, of the same length as the strongly curved spinulate feet.
Dimensions.—Shell 0.09 long, 0.11 broad.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
3. Pteroscenium pinnatum, n. sp. (Pl. [53], figs. 14, 15, 16).
Shell campanulate, smooth, somewhat longer than broad, with irregular delicate network of small roundish pores. Columella straight, with numerous (eight to twelve) triradiate verticils of ascending lateral branches, which are inserted in the shell-wall. The uppermost end of the columella is a conical apical horn. The three divergent feet are smooth, slender, conical, slightly curved, about as long as the shell, pinnate, with six to ten pairs of ascending lateral branches, parallel to those of the columella and inserted on the three vaulted lateral wings. (Fig. 14 exhibits the outside of the shell, fig. 15 the internal structure of the cortina, fig. 16 the basal view.)
Dimensions.—Shell 0.1 long, 0.12 broad.
Habitat.—Central Pacific, Station 274, depth 2750 fathoms.
4. Pteroscenium spinulosum, n. sp.
Shell campanulate, spinulate, about as long as broad, with small and numerous irregular polygonal pores, very similar to the preceding species, but differing in the more slender form of the horn and the feet, bearing more numerous lateral branches (twelve to sixteen pairs on each foot). Columella with six to eight triradiate verticils. Horn about as long as the shell.
Dimensions.—Shell 0.1 long, 0.1 broad.