Subgenus 1. Calpocapsa, Haeckel.
Definition.—Surface of the shell smooth or rough, but not spiny.
1. Halicapsa lithapium, n. sp. (Pl. 97, fig. 6).
Shell pear-shaped, rough, one and a half times as long as broad. Pores subregular, circular, twice as broad as the bars. Basal plate with four larger ovate cortinar pores (two larger cardinal and two smaller jugular), and with six smaller peripheral pores (fig. 6). Horn of the apex three-sided pyramidal, stout, half as long as the shell.
Dimensions.—Shell 0.16 long, 0.1 broad; horn 0.08 long.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
2. Halicapsa triglochin, n. sp. (Pl. 53, figs. 3, 4).
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.
Shell bottle-shaped, papillate, one and a half times as long as broad. Pores circular, much larger in the middle part than towards the poles. The elevated frames between them bear on the
