seven or nine, more or less irregular), conical, about as long as the diameter of the disk, without a connecting equatorial girdle.
Dimensions.—Diameter of the disk 0.15, of the medullary shell 0.05; length of the radial spines 0.16, basal breadth 0.01.
Habitat.—Pacific, central area, Station 271, depth 2425 fathoms.
3. Heliosestrum solarium, Haeckel.
Surface of the disk smooth; its diameter six times as large as that of the medullary shell. Pores regular, circular; nine to ten on the radius. Eight marginal spines regularly distributed (sometimes seven or nine, more or less irregular), conical, about as long as the diameter of the medullary shell, without a connecting equatorial girdle.
Dimensions.—Diameter of the disk 0.18, of the medullary shell 0.03; length of the radial spines 0.03, basal breadth 0.01.
Habitat.—Fossil in the Tertiary rocks of Barbados.
4. Heliosestrum liriope, n. sp.
Surface of the disk smooth; its diameter four times as large as that of the medullary shell. Pores subregular, circular; seven to eight on the radius. Eight marginal spines regularly distributed, conical, compressed, alternating longer and shorter; the longer equal to the diameter of the disk, the shorter to the radius.
Dimensions.—Diameter of the disk 0.16, of the medullary shell 0.4; length of the major radial spines 0.15, of the minor 0.09.
Habitat.—North Pacific, Station 236, surface.
5. Heliosestrum quadrigeminum, n. sp.
Surface of the disk smooth; its diameter four times as large as that of the medullary shell. Pores irregular, roundish; six to seven on the radius. Eight marginal spines triangular, flat, regularly disposed, alternating longer and shorter, the major as long as the radius of the shell, and half as broad at the base, with three to four deep furrows on both sides, without a connecting equatorial girdle.
Dimensions.—Diameter of the disk 0.16, of the medullary shell 0.04; length of the larger radial spines 0.08, of the smaller 0.04, basal breadth 0.04.
Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.
6. Heliosestrum contiguum, Haeckel.
Disk with smooth surface, four times as broad as the medullary shell. Pores irregular, roundish, touching, with very thin bars; nine to ten on the radius. Eight marginal spines (often
