12. Xiphosphæra ceres, n. sp.
Pores irregular, roundish, of different sizes, two to four times as broad as the bars. Sixteen to twenty pores on the half equator. Shell thin walled, with smooth surface. Polar spines conical, about as long as the axis of the sphere, very thick at the base.
Dimensions.—Diameter of the sphere 0.15 to 0.2, pores 0.004 to 0.008, bars 0.002; polar spines 0.18 to 0.24 long, at the base 0.02 thick.
Habitat.—North Atlantic, Station 353, surface.
13. Xiphosphæra clavigera, n. sp.
Pores irregular, roundish, double contoured, of very unequal size, two to seven times as broad as the bars; ten to twelve on the half equator. Shell thick walled; surface a little rough. Polar spines club-shaped, with prominent edges, about half as long as the axis of the sphere; thinner at both ends than in the middle. (Differs from Ellipsoxiphus claviger, Pl. 14, fig. 3, in the spherical shell and shorter spines.)
Dimensions.—Diameter of the sphere 0.2, pores 0.005 to 0.02, bars 0.003; polar spines 0.06 long, 0.02 broad.
Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.
Definition.—Pores of the spherical shell irregular, of different size or form; surface thorny or spiny (besides the two large polar spines).
14. Xiphosphæra vesta n. sp. (Pl. 14, fig. 6).
Pores irregular, roundish, three to five times as broad as the bars; fourteen to sixteen on the half equator. Scattered on the surface of the thick-walled shell are from twenty to thirty strong three-sided pyramidal spines of unequal size, the largest twice as long as the largest pores. Polar spines very strong, nearly three-sided prismatic, with curved edges, nearly as long as the axis of the sphere and twice as broad as the largest pores.
Dimensions.—Diameter of the sphere 0.17, pores 0.01 to 0.02, bars 0.004; length of the polar spines 0.13, thickness 0.02 to 0.03.
Habitat.—Pacific, central area. Station 266, depth 2750 fathoms,
15. Xiphosphæra astræa, n. sp.
Pores irregular, roundish, one to two times as broad as the bars; ten to twelve on the half equator. Surface of the thick-walled shell covered with numerous short conical thorns. Polar spines cylindro-conical, one and a half to two times as long as the axis of the sphere.
Dimensions.—Diameter of the sphere 0.18, pores 0.01 to 0.015, bars 0.008; length of the polar spines 0.25 to 0.3, thickness 0.02.
Habitat.—Indian Ocean, surface; Ceylon, Haeckel.
Definition.—Stylosphærida with one single lattice-sphere and two free spines of different size or form.
The genus Xiphostylus differs from the foregoing Xiphosphæra in the unequal size or form of both polar spines, which become more or less differentiated.
Definition.—Pores of the spherical shell regular, of nearly equal size and form; surface smooth or a little rough, without spines or thorns.
1. Xiphostylus alcedo, n. sp. (Pl. 13, fig. 4).
Pores regular, circular, with elevated hexagonal frames, twice as broad as the bars. Eight to ten pores on the half equator. Surface smooth. Polar spines three-sided pyramidal, as broad at the base as one hexagon; the major spine four to five times as long as the minor, which is about equal to the radius of the sphere.
Dimensions.—Diameter of the sphere 0.12, pores 0.012, bars 0.006; length of the major polar spine 0.16 to 0.2, of the minor 0.04 to 0.06, basal breadth 0.02.
Habitat.—Western Tropical Pacific, Station 225, depth 4475.
2. Xiphostylus phasianus, n. sp. (Pl. 13, fig. 9).
Pores regular, circular, twice as broad as the bars. Eight to ten pores on the half equator. Outer opening of each pore elegantly lobed, with eight indentations. Surface a little rough. Polar spines very unequal; major spine sword-like, sharply edged, about as long as the diameter of the sphere; minor spine scarcely half so long, pommel-shaped, with nine (?) wing-like edges.
Dimensions.—Diameter of the sphere 0.13, inner circular opening of the pores 0.01, outer eight-lobed opening 0.015, bars 0.005; length of the major polar spine 0.14, of the minor 0.06, breadth 0.03.
Habitat.—Australian Sea, Station 162, surface.
3. Xiphostylus motacilla, n. sp.
Pores regular, circular, three times as broad as the bars; sixteen to twenty on the half equator. Surface smooth. Polar spines compressed, two-edged, at the base three to four times as broad as one pore; the major spine somewhat longer than the diameter of the shell, the minor scarcely one-third or one-half as long.
Dimensions.—Diameter of the sphere 0.14, pores 0.006, bars 0.002; length of the major spine 0.16 to 0.18, of the minor 0.05 to 0.07, basal breadth 0.02.
Habitat.—Indian Ocean, Zanzibar, 2200 fathoms, Pullen.
4. Xiphostylus gallus, n. sp.
Pores regular, circular, five times as broad as the bars. Twelve to sixteen pores on the half equator. Surface smooth. Polar spines very unequal; the major conical spine one and a half to three times as long as the diameter of the sphere; the minor pommel-shaped, scarcely one-third as long (length of both spines very variable).
Dimensions.—Diameter of the sphere 0.13, pores 0.01, bars 0.002; length of the major spine 0.2 to 0.4, of the minor 0.05 to 0.08.
Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.
5. Xiphostylus alauda, n. sp. (Pl. 14, fig. 15).
Lithomespilus alauda, Haeckel, 1881, Prodrom. et Atlas, loc. cit.
Pores subregular, circular, three to four times as broad as the bars; fifteen to eighteen on the half equator. Surface a little rough. Polar spines irregularly conical or pyramidal, scarcely as long as the radius of the sphere; one spine simple, the other composed of a bunch of four or five spines united at the base.
Dimensions.—Diameter of the sphere 0.11, pores 0.01, bars 0.003; length of the polar spines 0.03 to 0.05, basal breadth 0.02.
Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.
6. Xiphostylus anhinga, Haeckel.
Rhabdolithis pipa, Bury, 1862, Polycystins of Barbados, pl. iii. fig. 4.
Pores subregular, circular, about the same breadth as the bars; eight to ten on the half equator. Surface smooth or a little rough. Polar spines cylindrical, very irregularly curved like S or contorted, the major three to six times as long as the diameter of the sphere, the minor scarcely one-fourth as long as the former, at the end truncated.
Dimensions.—Diameter of the sphere 0.07, pores and bars 0.005; length of the major polar spine 0.2 to 0.4, of the minor 0.06 to 0.09, basal breadth 0.01.
Habitat.—Fossil in the Barbados rocks.
Definition.—Pores of the spherical shell regular, of nearly equal size and form; surface thorny or spiny (other than the two large polar spines).
7. Xiphostylus cuculus, n. sp.
Pores regular, circular, hexagonally framed, three times as broad as the bars; ten to twelve on the half equator. Surface thorny, between every three pores a short conical thorn. Polar spines three-sided prismatic, the major somewhat longer than the diameter of the sphere, the minor scarcely one-third as long, pommel-shaped.
Dimensions.—Diameter of the sphere 0.17, pores 0.012, bars 0.004; length of the major polar spine 0.2, of the minor 0.05, basal breadth 0.015.
Habitat.—South Atlantic, surface; Station 335, depth 1425 fathoms.
8. Xiphostylus trochilus, n. sp. (Pl. 13, fig. 10).
Pores regular, circular, four times as broad as the bars; eight to nine on the half equator. Polar spines cylindrical, the major somewhat longer than the axis of the sphere, the minor shorter, surrounded by a group of from four to eight shorter conical spines. Surface of the opposite hemisphere smooth, without by-spines.
Dimensions.—Diameter of the sphere 0.07 to 0.08, pores 0.01, bars 0.0025.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
9. Xiphostylus picus, n. sp. (Pl. 14, fig. 13).
Lithomespilus picus, Haeckel, 1881, Prodrom. et Atlas.
Pores regular, circular, twice as broad as the bars; sixteen to eighteen on the half equator. Polar spines cylindrical, conical at the apex, the major once and a half to twice as long as the diameter of the shell, the minor scarcely half so long; around the latter a group of twelve to twenty shorter conical spines, irregularly scattered. Surface of the other hemisphere smooth.
Dimensions.—Diameter of the sphere 0.13, pores 0.006, bars 0.003; length of the major polar spine 0.2 to 0.24, of the minor 0.08 to 0.09, basal breadth 0.02.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
Definition.—Pores of the spherical shell irregular, of unequal size or form; surface smooth or a little rough, without thorns.
10. Xiphostylus trogon, n. sp. (Pl. 14, fig. 12).
Lithomespilus trogon, Haeckel, 1881, Prodrom. et Atlas.
Pores irregular, roundish or subcircular, two to three times as broad as the bars; ten to twelve on the half equator. Surface smooth. Major polar spine three-sided prismatic, once and a half to twice as long as the axis of the sphere; minor spine quite rudimentary, scarcely longer than broad, but surrounded by a group of from three to six similar short spines.
Dimensions.—Diameter of the sphere 0.1, pores 0.005 to 0.015, bars 0.005 to 0.008; length of the major spine 0.15 to 0.18, of the minor 0.01 to 0.02, basal breadth 0.02.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
11. Xiphostylus falco, n. sp. (Pl. 13, fig. 14).
Pores irregular, roundish, two to five times as broad as the bars; sixteen to eighteen on the half equator. Surface smooth. Polar spines cylindrical, very stout, nearly half as thick as the radius of the shell; major spine two to four times as long as the diameter of the shell; minor spine obliquely inserted, scarcely longer than the diameter, divided at the end into two short, hook-shaped, curved branches.
Dimensions.—Diameter of the sphere 0.08, pores 0.002 to 0.005, bars 0.001; breadth of the spines 0.02, length of the major spine 0.15 to 0.2, of the minor 0.09.
Habitat.—South Pacific, Station 302, depth 1450 fathoms.
12. Xiphostylus alca, n. sp. (Pl. 13, fig. 13).
Pores irregular, roundish, two to six times as broad as the bars; six to eight on the half equator. Each pore with three to six lobes, composed of three to six confluent smaller pores. Surface smooth. Major spine conical, curved, somewhat longer than the axis of the sphere; minor spine somewhat shorter, pommel-like, edged.
Dimensions.—Diameter of the sphere 0.07, pores 0.01 to 0.02, bars 0.003; length of the major spine 0.08, of the minor 0.06, basal thickness 0.02.
Habitat.—Indian Ocean, Sunda Strait, Rabbe, surface.
13. Xiphostylus edolius, n. sp. (Pl. 13, fig. 5).
Pores irregular, roundish, composed of two to six smaller confluent pores. On the half equator six to eight large pores, and twenty to thirty small pores; bars between the smaller very thin. Surface a little rough. Major polar spine conical, S-shaped, about twice as long as the axis of the shell; minor spine pommel-shaped, edged, scarcely as long as its radius.
Dimensions.—Diameter of the sphere 0.12, large pores 0.01 to 0.03, small pores 0.004 to 0.008, bars 0.001 to 0.004; length of the major spine 0.2, of the minor 0.05, basal breadth 0.02.
Habitat.—Central Pacific, Station 273, surface.
Definition.—Pores of the spherical shell irregular, of different size or form; surface thorny or spiny.
14. Xiphostylus emberiza, n. sp. (Pl. 13, fig. 11).
Pores irregular, roundish, one to four times as broad as the bars; six to eight on the half equator. Polar spines very unequal; major cylindrical, twice as long as the axis of the sphere; minor scarcely half as long, obliquely inserted, like a bird's head, surrounded by a group of ten to twenty smaller conical spines. Opposite hemisphere smooth.
Dimensions.—Diameter of the sphere 0.005, pores 0.002 to 0.008, bars 0.002; length of the major spine 0.09, of the minor 0.05, basal breadth 0.01.
Habitat.—South Atlantic, Station 332, surface.
15. Xiphostylus ardea, n. sp.
Pores irregular, roundish, one to three times as broad as the bars; twelve to sixteen on the half equator. Whole surface spiny. Major polar spine three-sided pyramidal, somewhat longer than the diameter of the sphere; minor scarcely so long as its half radius, pommel-like, edged.
Dimensions.—Diameter of the sphere 0.12, pores 0.003 to 0.01, bars 0.003; length of the major polar spine 0.15, of the minor 0.03, basal breadth 0.02.
Habitat.—North Atlantic, Station 64, surface.
Definition.—Stylosphærida with one single lattice-sphere and two equal opposite spines, connected at the distal end by a circular or elliptical ring.
The genus Saturnalis (with simple lattice-sphere) and the two similar genera Saturnulus (with two concentric spheres) and Saturninus (with three spheres) form together the small peculiar group of Saturnalida, distinguished by a remarkable circular or elliptical ring, connecting the distal ends of the two equal opposite polar spines. This ring indicates a certain equatorial plane, and therefore brings these Sphæroidea into relation with the Discoidea.
Definition.—Ring smooth, without spines or thorns.
1. Saturnalis circularis, n. sp.
Pores of the spherical shell regular, circular, hexagonally framed, twice as broad as the bars. Ten to twelve pores on the half equator. Ring circular, smooth, its diameter three times as great as that of the sphere.
Dimensions.—Diameter of the sphere 0.07, pores 0.005, bars 0.0025; diameter of the circular ring 0.2, thickness of the axial beams and the ring 0.01.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
2. Saturnalis annularis, n. sp. (Pl. 13, fig. 16).
Pores of the spherical shell regular, circular, with elevated hexagonal frames, of the same breadth as the bars. Sixteen to twenty pores on the half equator. Ring elliptical, smooth, somewhat constricted at the poles of the axis, its diameter three times as great as that of the sphere.
Dimensions.—Diameter of the sphere 0.09, pores and bars 0.005, major axis of the elliptical ring 0.27 to 0.3, minor axis 0.19 to 0.2; thickness of the ring and of the axial beams 0.01.
Habitat.—Pacific, central area, Stations 270 to 274, surface.
3. Saturnalis cyclus, n. sp.
Lithocircus mesocena, Bury, 1862, Polycystins of Barbados, pl. iii. fig. 1.
Pores of the spherical shell regular, circular, without hexagonal frames, twice as broad as the bars. Eight to ten pores on the half equator. Ring circular, smooth, its diameter four times as great as that of the sphere.
Dimensions.—Diameter of the sphere 0.07, pores 0.006, bars 0.003; diameter of the circular ring 0.28, thickness of the ring and both axial beams 0.01.
Habitat.—Fossil in the Barbados rocks.
4. Saturnalis circoides, n. sp. (Pl. 13, fig. 12).
Pores of the spherical shell irregular, roundish, often somewhat lobed, one to three times as broad as the bars; fifteen to twenty on the half equator. Ring circular, smooth, with four prominent edges, its diameter twice as great as that of the sphere. (The figured specimen is a young or not fully developed one; afterwards I found in the same locality other specimens with quite perfect rings, similar to the edged ring of Saturnulus annulus, Pl. 16, fig. 17.)
Dimensions.—Diameter of the sphere 0.09 to 0.1, pores 0.003 to 0.01, bars 0.004; diameter of the circular ring 0.2 to 0.24, thickness of the ring and the polar beams 0.01.
Habitat.—Indian Ocean; fossil in the Nicobar rocks; living at great depths near Zanzibar, 2200 fathoms, Pullen.
Definition.—Ring armed on the periphery with numerous spines or thorns.
5. Saturnalis trochoides, n. sp.
Haliomma species, Bury, 1862, Polycystins of Barbados, pl. xx. fig. 2.
Pores of the spherical shell subregular, circular, twice as broad as the bars. Twelve to sixteen pores on the half equator. Ring circular, armed with ten to twelve strong conical, irregular spines, its diameter twice as great as that of the sphere.
Dimensions.—Diameter of the sphere 0.08, pores 0.006, bars 0.003; diameter of the circular ring 0.16; length of the radial spines 0.02 to 0.04; thickness of the ring and the axial beams 0.01.
Habitat.—Fossil in the Barbados rocks.
6. Saturnalis rotula, n. sp. (Pl. 13, fig. 15).
Pores of the spherical shell regular, circular, twice as broad as the bars; sixteen to twenty on the half equator. Ring circular, armed with fifteen to twenty strong, conical, irregular spines, partly simple, partly divided into two or three irregular branches; diameter of the ring two and a half times as great as that of the sphere.
Dimensions.—Diameter of the sphere 0.08, pores 0.004, bars 0.002; diameter of the circular ring 0.2, length of its spines 0.02 to 0.03; thickness of the ring and the radial beams 0.01.
Habitat.—North Pacific, Station 244, surface.
Definition.—Stylosphærida with two concentric, spherical lattice-shells.
Definition.—Stylosphærida with two concentric lattice-spheres and two free spines of equal size and similar form.
The genus Stylosphæra, the most simple form of the Sphærostylida, can be derived either from Xiphosphæra by duplication of the spherical shell, or from Carposphæra by development of two opposite polar spines. The inner or medullary shell is enclosed in the central capsule, whilst the outer or cortical shell lies outside it; the two are connected by two or more radial beams, piercing the wall of the capsule.
Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; surface smooth or a little rough, without spines or thorns.
1. Stylosphæra musa, n. sp.
Radial proportion of the two concentric spheres = 3 : 1. Cortical shell thin walled, smooth, with regular, hexagonal pores, three times as broad as the thin bars; twelve on the half equator. Polar spines three-sided pyramidal, as long as the axis of the cortical shell, one-tenth as broad at the base.
Dimensions.—Diameter of the outer shell 0.2, pores 0.01, bars 0.003; diameter of the inner shell 0.06; length of the polar spines 0.2, basal breadth 0.02.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
2. Stylosphæra urania, n. sp.
Radial proportion of the two shells = 4 : 1. Cortical shell thin walled, smooth; pores regular, circular, hexagonally framed, twice as broad as the bars; ten on the half equator. Polar spines conical, as long as the radius of the outer shell.
Dimensions.—Diameter of the cortical shell 0.24, pores 0.012, bars 0.006; medullary shell 0.06; length of the polar spines 0.12, basal breadth 0.024.
Habitat.—South Pacific, Station 285, depth 2375 fathoms.
3. Stylosphæra calliope, n. sp. (Pl. 16, fig. 6).
Radial proportion of the two shells = 3 : 1. Cortical shell thick walled, smooth; pores regular, circular, three times as broad as the bars. Each pore on its outer opening with eight regular lobules, flower-like. Nine to ten pores on the half equator. Polar spines three-sided pyramidal, with three strong prominent edges, about as long as the axis, as broad as one pore. (Sometimes, as in the figured specimen, one spine is smaller than the other; this variety, otherwise identical, may be called Sphærostylus calliope.)
Dimensions.—Diameter of the outer shell 0.12, pores 0.015, bars 0.005; inner shell 0.04; length of the polar spine 0.08 to 0.12, breadth 0.02.
Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.
4. Stylosphæra clio, n. sp. (Pl. 16, fig. 7).
Radial proportion of the two shells = 2 : 1. Cortical shell thick walled, smooth; pores regular, circular, three times as broad as the bars; fourteen to sixteen on the half equator. Polar spines three-sided pyramidal, very robust, with thick prismatic edges, about as long as the axis of the cortical shell, one-third as broad at the base. (Sometimes, as in the figured specimen, one spine is greater than the other; this form may be called Sphærostylus clio.)
Dimensions.—Diameter of the outer shell 0.12, pores 0.01, bars 0.003; inner shell 0.06; length of the polar spines 0.08 to 0.12, basal breadth 0.03 to 0.04.
Habitat.—Pacific, central area; Station 272, depth 2600 fathoms.
5. Stylosphæra polyhymnia, n. sp.
Radial proportion of the two spheres = 3 : 1. Cortical shell very thin walled, smooth, with regular, circular pores, three times as broad as the bars; sixteen to twenty on the half equator. Polar spines cylindrical, pointed, once and a half to twice as long as the axis of the outer sphere, scarcely broader than one pore. The two spheres are connected only by the two opposite beams.
Dimensions.—Diameter of the outer shell 0.12 to 0.16, pores 0.006 to 0.009, bars 0.002 to 0.003; inner shell 0.04 to 0.05; length of the polar spines 0.18 to 0.22, breadth 0.01.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.
6. Stylosphæra dixyphos, Haeckel.
Haliomma dixyphos, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 83; Mikrogeol., Taf. xxii. fig. 31.
Haliomma dixyphos, Haeckel, 1862, Monogr. d. Radiol. p. 433.
Radial proportion of the two spheres = 2 : 1. Cortical shell thin walled, smooth, with regular, circular pores, twice as broad as the bars; ten to twelve on the half equator. Polar spines about as long as the axis of the outer shell, three-sided pyramidal, at the base twice as broad as one pore. (The two spheres connected by four beams, two opposite in the main axis, two opposite in the equatorial axis.)
Dimensions.—Diameter of the outer shell 0.1, pores 0.01, bars 0.05; inner shell 0.05; length of the polar spines 0.08 to 0.1, basal breadth 0.02.
Habitat.—South Atlantic, Station 332, surface; fossil in Tertiary rocks of Sicily.
Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; surface thorny or spiny.
7. Stylosphæra setosa, Ehrenberg, 1872.
Stylosphæra setosa, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 320; Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. viii. fig. 15.
Radial proportion of the two shells = 2 : 1. Cortical shell thin walled, spiny; pores regular, hexagonal, four times as broad as the bars. Six to eight pores on the half equator. Polar spines conical, thin, scarcely as long as the radius of the cortical shell.
Dimensions.—Diameter of the cortical shell 0.1, pores 0.002, bars 0.005; medullary shell 0.05; length of the polar spines 0.04, basal breadth 0.01.
Habitat.—Philippine Sea, depth 3300 fathoms, Ehrenberg; Station 206, depth 2100 fathoms.
8. Stylosphæra euterpe, n. sp.
Radial proportion of the two shells = 3 : 1. Cortical shell thin walled, spiny; pores regular, circular, with hexagonal frames, twice as broad as the bars; eight to ten on the half equator. Polar spines conical, as thick as one pore at the base, about as long as the axis of the cortical shell.
Dimensions.—Diameter of the cortical shell 0.12, pores 0.012, bars 0.006; medullary shell 0.04; length of the polar spines 0.1, basal breadth 0.012.
Habitat.—South Pacific, Station 302, depth 1450 fathoms.
9. Stylosphæra melpomene, n. sp. (Pl. 16, fig. 1).
Radial proportion of the two shells = 3 : 1. Cortical shell thin walled, spiny, with regular, circular pores, four times as broad as the bars; eight to ten on the half equator. Polar spines three-sided prismatic, pointed, as broad as one pore, only one-third as long as the axis of the sphere (the two shells connected by four thin beams, two opposite in the main axis, two in the equatorial axis).
Dimensions.—Diameter of the outer shell 0.12, pores 0.012, bars 0.003; inner shell 0.04; length of the polar spines 0.04, thickness 0.013.
Habitat.—Indian Ocean, Cocos Islands, Rabbe.
10. Stylosphæra hispida, Ehrenberg, 1854.
Stylosphæra hispida, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 246; Mikrogeol, Taf. xxxvi. fig. 26.
Haliomma hispidum, Haeckel, 1862, Monogr. d. Radiol., p. 433.
Radial proportion of the two spheres = 3 : 1. Cortical shell thick walled, spiny, with regular, circular pores of the same breadth as the bars; ten to fifteen on the half equator. Polar spines three-sided prismatic, pointed, about as long as the axis of the outer sphere, nearly as broad at the base as the inner sphere. (Compare Sphærostylus hispidus; also Ehrenberg, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1874, p. 259.)
Dimensions.—Diameter of the outer shell 0.1 to 0.12, pores and bars 0.004; inner shell 0.04; length of the polar spines 0.1 to 0.15, basal breadth 0.03.
Habitat.—Fossil in the Tertiary rocks of Sicily, Barbados, Nicobars, &c.
11. Stylosphæra liostylus, Ehrenberg, 1875.
Stylosphæra liostylus, Ehrenberg, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 84, Taf. xxv. fig. 3.
Radial proportion of the two spheres = 3 : 1. Cortical shell thick walled, thorny, with regular, circular pores, three times as broad as the bars; eight to ten on the half equator. Polar spines conical, once and a half to twice as long as the axis of the outer sphere, half as broad at the base as its radius. (This species, common in the Barbados rocks, is different from Sphærostylus liostylus, loc. cit., fig. 2, which Ehrenberg believed identical.)
Dimensions.—Diameter of the outer shell 0.1, pores 0.01, bars 0.0035; inner shell 0.03; length of the polar spines 0.14 to 0.18, basal breadth 0.02.
Habitat.—Fossil in the Barbados rocks; living in the depths of the North Atlantic, Gulf Stream, Florida.
Definition.—Pores of the cortical shell irregular, of different size or form; surface smooth or a little rough, without thorns or spines.
12. Stylosphæra nana, n. sp. (Pl. 16, figs. 12, 13).
Radial proportion of the two spheres = 2 : 1. Cortical shell thick walled, somewhat irregular, smooth, with irregular, roundish pores, one to three times as broad as the bars; eight to ten on the half equator. Polar spines three-sided pyramidal, scarcely as long as the axis of the outer sphere, and nearly as broad at the base as its radius. (A very variable and irregular form.)
Dimensions.—Diameter of the outer shell 0.07 to 0.09, pores 0.003 to 0.009, bars 0.003; inner shell 0.03 to 0.04; length of the polar spines 0.04 to 0.07, basal breadth 0.03.
Habitat.—North Pacific, Stations 241 to 253, surface.
13. Stylosphæra jugata, n. sp.
Radial proportion of the two shells = 2 : 1. Cortical shell thick walled, smooth, with irregular, roundish, double-contoured pores, confluent in groups of two to six. On the half equator six to nine groups and fifteen to twenty pores; bars between them of very variable breadth. Polar spines very strong, three-sided pyramidal, twice as long as the axis of the outer sphere, half as broad at the base as its radius. (Nearly allied to Lithatractus jugatus, Pl. 16, fig. 2, but differs in the truly spherical form of both shells and the double length of the polar spines.)
Dimensions.—Diameter of the outer shell 0.15, pores 0.005 to 0.02; inner shell 0.07; length of the polar spines 0.25 to 0.3, basal breadth 0.03.
Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.
14. Stylosphæra terpsichore, n. sp.
Radial proportion of the two shells = 3 : 1 or 4 : 1. Cortical shell thick walled, smooth, with irregular, roundish pores, one to three times as broad as the bars; fifteen to twenty-five on the half equator. Polar spines conical, about as long as the axis of the outer sphere, as broad at the base as the inner shell.
Dimensions.—Diameter of the outer shell 0.15 to 0.2, pores 0.005 to 0.02, bars 0.004 to 0.008; inner shell 0.05; length of the polar spines 0.15 to 0.25, basal breadth 0.05.
Habitat.—Western Indian Ocean, Zanzibar, depth 2200 fathoms, Pullen.
Definition.—Pores of the cortical shell irregular, of different size or form; surface spiny or thorny.
15. Stylosphæra thalia, n. sp.
Radial proportion of the two shells = 2 : 1. Cortical shell thin walled, thorny, with irregular, roundish pores, two to four times as broad as the bars; eight to twelve on the half equator. Polar spines conical, one to one and a half times as long as the axis of the outer sphere, one-fourth to one-sixth as thick at the base. (Resembles Sphærostylus ophidium, Pl. 16, fig. 14, but differs in the straight regular conical polar spines, both of equal length and similar form.)
Dimensions.—Diameter of the outer shell 0.12, pores 0.01 to 0.02, bars 0.005; inner shell 0.06; polar spines 0.1 to 0.16 long, 0.03 broad.
Habitat.—South Pacific, Station 302, depth 1450 fathoms.
16. Stylosphæra erato, n. sp.
Radial proportion of the two shells = 3 : 1. Cortical shell thick walled, thorny, with irregular, roundish pores, two to five times as broad as the bars; fourteen to eighteen on the half equator. Polar spines three-sided pyramidal, about as long as the axis of the outer sphere, one-fourth as broad as its radius. (Similar to Xiphosphæra vesta, Pl. 14, fig. 6.)
Dimensions.—Diameter of the outer shell 0.15, pores 0.008 to 0.015, bars 0.003; inner shell 0.05; polar spines 0.12 long, 0.02 broad.
Habitat.—South Atlantic, Station 335, depth 1425 fathoms.
Definition.—Stylosphærida with two concentric lattice-spheres and two free spines, of different size or form.
The genus Sphærostylus differs from Stylosphæra in the different size or form of the two polar spines, and therefore has the same relation to it that Xiphostylus bears to Xiphosphæra.
Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; surface smooth or a little rough, without thorns.
1. Sphærostylus liostylus, Haeckel.
Stylosphæra liostylus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. xxv. fig. 2.
Cortical shell thin walled, with rough surface, three times as broad as the medullary shell. Pores of the cortical shell regular, circular, twice as broad as the bars; ten to twelve on the half equator. Polar spines cylindrical, as broad as one pore, with conical apex; the minor spine about as long as the axis of the outer shell, the major three to four times as long.
Dimensions.—Diameter of the outer sphere 0.12, pores 0.12, bars 0.006; diameter of the inner sphere 0.04; length of the major polar spine 0.3 to 0.4, of the minor 0.1 to 0.15, breadth 0.012.
Habitat.—Fossil in the Barbados rocks.
2. Sphærostylus flexuosus, Haeckel.
Stylosphæra flexuosa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. xxv. fig. 5.
Cortical shell thick walled, with rough surface, three times as broad as the medullary shell. Pores of the cortical shell regular circular, of the same breadth as the bars; eight to ten on the half equator. Polar spines cylindrical, S-like curved, irregular; the minor scarcely as long as the axis of the outer sphere, the major two to three times as long. (In the figure of Ehrenberg the spines are broken off; I have found them myself constantly irregular and of unequal length, sometimes with conical apex.)
Dimensions.—Diameter of the outer sphere 0.08, pores and bars 0.006; inner sphere 0.03; length of the major polar spine 0.15 to 0.25, of the minor 0.07 to 0.09, breadth 0.02.
Habitat.—Fossil in the Barbados rocks.
3. Sphærostylus clio, n. sp.
Cortical shell thick walled, with smooth surface, twice as broad as the medullary shell; its network has regular, circular pores, three times as broad as the bars; sixteen to twenty on the half equator. Polar spines very strong, three-sided pyramidal; the major nearly twice as long as the axis of the outer sphere, the minor scarcely as long as its radius. (Nearly related to Stylosphæra clio, Pl. 16, fig. 7, but differs in the slender form and unequal length of the polar spines.)
Dimensions.—Diameter of the outer sphere 0.14, pores 0.01, bars 0.03; inner sphere 0.07; length of the major spine 0.25, of the minor 0.06, basal breadth 0.02.
Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.
4. Sphærostylus hippocampus, n. sp. (Pl. 16, figs. 10, 11).
Cortical shell thick walled, with smooth surface and regular network; the pores circular, hexagonally-lobed, three times as broad as the bars; ten to twelve on the half equator. Medullary shell half as large, with very small circular pores, eight to ten on the half equator. Major polar spine scarcely as long as the axis of the outer shell, curved like a horn; minor spine scarcely half as long, pommel-like, edged. (Sometimes, by prolongation of the main axis, the spherical shells become ellipsoidal and thus the species is transformed into Druppatractus hippocampus.)
Dimensions.—Diameter of the outer sphere 0.08, pores 0.009, bars 0.003; inner sphere 0.04; length of the major spine 0.07, of the minor 0.03, breadth 0.02.
Habitat.—Pacific, central area, Station 270, depth 2925 fathoms.
Definition.—Pores of the cortical shell regular, of nearly equal size and form; surface spiny or thorny.
5. Sphærostylus diadema, n. sp.
Cortical shell thick walled, spiny, twice as broad as the medullary shell, with regular, circular pores, twice as broad as the bars; eight to ten on the half equator. Major polar spine about as long as the axis of the outer sphere, three-sided pyramidal; minor spine scarcely half as long, pommel-shaped, edged. (Similar in general form to Xiphatractus glyptodon, Pl. 17, figs. 9, 10; but differs in the simple medullary shell, the spherical form of both shells, and the simple circular regular pores.)