Subgenus 1. Tripodiscinus, Haeckel.
Definition.—Feet simple, not branched nor forked.
1. Tripodiscium tristylospyris, n. sp.
Shell subspherical, with regular, circular pores, twice as broad as the bars. Mouth constricted, half as broad as the shell, with three short spindle-shaped feet, which are nearly parallel and vertical, half as long as the shell. (Similar to Tristylospyris scaphipes, Pl. [84], fig. 13, but without sagittal ring and constriction.)
Dimensions.—Shell 0.08 long, 0.07 broad; feet 0.04 long.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
2. Tripodiscium ovatum, n. sp.
Shell ovate, rough, nearly as broad as long. Pores regular circular, double-contoured, twice as broad as the bars. Mouth constricted, one-third as broad as the shell, with three convergent short triangular feet.
Dimensions.—Shell 0.1 long, 0.09 broad; feet 0.02 long.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.