Subgenus 1. Acrocorona, Haeckel, 1881, Prodromus, p. 430.
Definition.—Feet simple, not branched nor forked.
1. Calpophæna tetrarrhabda, n. sp.
Shell subspherical, tuberculate, with subregular circular pores. Apical horn conical, about as long as the shell. Basal plate with a regular cross of four equal cortinar pores, separated by four bars; these are crossed in the sagittal and frontal diameter, and prolonged into four equal conical divergent feet, about as long as the shell.
Dimensions.—Shell 0.1 diameter, horn and feet 0.1 to 0.12 long.
Habitat.—South Pacific, Station 297, depth 1775 fathoms.
2. Calpophæna hexarrhabda, n. sp. (Pl. 53, figs. 17, 18).
Shell subspherical, rough, with irregular roundish pores. Apical horn conical, shorter than the shell. Basal plate (fig. 18) with three pairs of triangular pores, two larger (cardinal) pores in the middle, two smaller (cervical) at the dorsal, and two intermediate (jugular) at the ventral side. The bars between them are prolonged into six equal cylindrical divergent feet, nearly as long as the shell, provided with a spiny knob at the end.
Dimensions.—Shell 0.09 long, 0.08 broad; horn and feet 0.06 to 0.08 long.
Habitat.—Tropical Pacific, Station 224, depth 1850 fathoms.
3. Calpophæna ennearrhabda, n. sp.
Shell subspherical, spiny, with irregular, roundish pores. Apical horn cylindrical, longer than the shell. Basal plate with nine collar pores, three larger central alternating with three pairs of smaller peripheral (like Pl. 87, fig. 2). Corona with nine slender cylindrical, slightly curved, divergent feet, somewhat longer than the shell.
Dimensions.—Shell 0.11 long, 0.1 broad; horn and feet 0.12 to 0.15 long.
Habitat.—North Pacific, Station 241, depth 2300 fathoms.
4. Calpophæna enneaphylla, n. sp.
Shell ovate, smooth, with regular circular pores. Apical horn pyramidal, half as long as the shell. (Basal plate with four cortinar pores?) Corona with nine broad, lamellar, truncate, vertical feet, about as long as the horn.
Dimensions.—Shell 0.12 long, 0.09 broad; horn and feet 0.06 long.
Habitat.—Central Pacific, Station 271, surface.
