Shell ovate, rough, a little longer than broad. Pores regular, circular, hexagonally framed, of the same breadth as the bars. Basal plate (fig. 4) without larger pores. Horn pyramidal, stout, about half as long as the shell, with three short, horizontally divergent secondary spines at the base (possibly remnants of three original cortinar feet?)
Dimensions.—Shell 0.11 long, 0.09 broad; horn 0.06 long.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
3. Halicapsa prunoides, n. sp.
Shell pear-shaped, tuberculate, a little longer than broad. Pores irregular, roundish, of different sizes. Basal plate with four larger and six smaller pores. Horn pyramidal, stout, about one-third as long as the shell. (May belong perhaps to the similar Prunoidea Lithapium, compare p. [303] and Pl. [14], figs. 8-10.)
Dimensions.—Shell 0.14 long, 0.12 broad; horn 0.05 long.
Habitat.—Fossil in Barbados.
Subgenus 2. Echinocapsa, Haeckel, 1881, Prodromus, p. 429.
Definition.—Surface of the shell spiny, covered with thorns, papillæ or larger spines.
4. Halicapsa papillata, n. sp.