numerous and stout; thirty to forty main spines, three-sided pyramidal, nearly as long as the radius, as broad as one mesh; by-spines small, conical, everywhere scattered at the nodal-points of the network and on the high combs of the bars.
Dimensions.—Diameter of the shell 0.16, pores 0.012, bars 0.004; length of the main spines 0.07, basal breadth 0.016.
Habitat.—West Tropical Pacific, Station 225, depth 4475 fathoms.
6. Heliosphæra coronata, n. sp. (Pl. 26, figs. 6, 6a).
Shell thick walled, about ten times as broad as one mesh. Pores regular, circular, five times as broad as the bars; each pore surrounded by a regular coronal of six short, conical by-spines (fig. 6a); twenty to thirty main spines, also conical, half as long as the radius, as broad as one pore.
Dimensions.—Diameter of the shell 0.15, pores 0.015, bars 0.003; length of the main spines 0.04, basal breadth 0.015.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
7. Heliosphæra floribunda, n. sp.
Shell thick walled about ten times as broad as one mesh. Pores regular, six-lobed, twice as broad as the bars; each pore surrounded by six small conical by-spines (as in Pl. 28, figs. 1, 1b); twenty main spines regularly disposed cylindro-conical, as long as the diameter of the shell or longer.
Dimensions.—Diameter of the shell 0.15, pores 0.015, bars 0.008; length of the main spines 0.16, breadth 0.008.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
8. Heliosphæra cristata, n. sp.
Shell thick walled, about twelve times as broad as one mesh. Pores subregular, circular, twice as broad as the bars; each pore surrounded by an elegant coronal of ten to twenty small, conical by-spines; twenty main spines regularly disposed, conical, only one-third as long as the radius, as broad at the base as one mesh.
Dimensions.—Diameter of the shell 0.25, pores 0.02, bars 0.01; length of the main spines 0.04, basal breadth 0.02.
Habitat.—South Pacific, Station 285, depth 2375 fathoms.
9. Heliosphæra castanella, n. sp.
Shell thick walled, about twenty times as broad as one mesh. Pores regular, circular, of the same breadth as the bars. Whole surface densely covered with innumerable bristle-shaped by-spines, half as long as the radius; fifty to eighty main spines, conical, nearly as long as the diameter,
