Definition.—Tholospyrida with numerous basal feet (eight to twelve or more). Galea with a horn.
The genus Sepalospyris has been derived from the similar Petalospyris by development of a galea or cupola on the coryphal face of the cephalis, or from Tholospyris by multiplication of the basal feet. The latter (in the two observed species from twelve to twenty-five) form a regular corona around the basal plate.
1. Sepalospyris platyphylla, n. sp. Pl. [95], fig. 15.
Shell ovate, rough, with sharp transverse stricture. Cupola with delicate network, hemispherical, about two-thirds as long and broad as the nut-shaped thorax. Pores of the latter irregular, roundish; two or three pairs of large pores on each side of the sagittal stricture. Apical horn conical, half as long as the shell. Basal coronet with twelve to fifteen broad, lamellar, truncate, vertical feet, somewhat shorter than the cephalis.
Dimensions.—Shell 0.12 long, 0.13 broad; ring 0.06 long; horn 0.04; feet 0.05 long.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
2. Sepalospyris polyphylla, n. sp.
Shell campanulate, rough, with deep transverse stricture. Cupola hemispherical, about one-third as long and broad as the nut-shaped thorax. Pores irregular, roundish, a little different in size. Apical horn pyramidal, about as long an the shell. Basal coronet with twenty to twenty-five slender, lamellar, pointed, vertical feet, longer than the shell.
Dimensions.—Shell 0.11 long, 0.12 broad; ring 0.07 long; horn 0.1; feet 0.12 to 0.18 long.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.