Definition.—Pores regular, all of nearly equal size and similar form; surface smooth.
1. Staurosphæra cruciata, n. sp.
Shell thin walled, smooth, with regular, hexagonal pores, four times as broad as the bars; ten to twelve on the quadrant. Four crossed radial spines three-sided pyramidal, as long as the diameter of the shell, as broad at the base as one pore (very similar to Hexastylus phænaxonius, Pl. 21, fig. 3, but with only four spines).
Dimensions.—Diameter of the shell 0.12, of the pores 0.008, bars 0.002.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
2. Staurosphæra christiana, n. sp.
Shell thick walled, smooth, with regular, circular, hexagonally framed pores, three times as broad as the bars; six to eight on the quadrant. Four crossed spines six-sided pyramidal, as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the shell 0.13, pores 0.012, bars 0.004.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
3. Staurosphæra johannis, n. sp.
Shell thick walled, smooth, with regular, circular pores, four times as broad as the bars; five to six on the quadrant. Four spines six-sided pyramidal, half as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the shell 0.15, pores 0.02, bars 0.005.
Habitat.—North Pacific, Station 241, depth 2300 fathoms.
4. Staurosphæra pauli, n. sp.
Shell very thick walled, smooth, with regular, circular, double-edged pores, four times as broad as the bars; eight to ten on the quadrant. Four spines conical, as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the shell 0.15, pores 0.016, bars 0.004.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
5. Staurosphæra petri, n. sp.
Shell thin walled, smooth, with regular, circular pores, three times as broad as the bars; twenty to twenty-two on the quadrant. Four spines conical, half as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the shell 0.22, pores 0.006, bars 0.002.
Habitat.—South Atlantic, Station 325, depth 2650 fathoms; also fossil in Barbados.
6. Staurosphæra jacobi, n. sp.
Shell thick walled, smooth, with regular, circular pores, twice as broad as the bars; eleven to twelve on the quadrant. Four spines cylindrical, three times as long as the radius, three times as broad as one mesh.
Dimensions.—Diameter of the shell 0.1, pores 0.006, bars 0.003.
Habitat.—North Atlantic, Station 353, depth 2965 fathoms.
7. Staurosphæra simonis, n. sp.
Haliomma with four spines, Bury, 1862, Polycystins of Barbados, pl. iv. fig. 4.
Shell thick walled, smooth, with regular, circular pores, of the same breadth as the bars; eight to ten on the quadrant. Four spines cylindrical, twice as long as the radius, five times as broad as one mesh.
Dimensions.—Diameter of the sphere 0.1, pores and bars 0.003.
Habitat.—Fossil in Barbados.
Definition.—Pores regular, all of nearly equal size and similar form; surface covered with by-spines or accessory thorns.
8. Staurosphæra philippi, n. sp. (Pl. 15, fig. 6).
Shell thin walled, covered with bristle-shaped by-spines, as long as the radius. Pores regular, circular, twice as broad as the bars; six to eight on the quadrant. Four main spines cylindrical, five to ten times as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the shell 0.08, pores 0.006, bars 0.003.
Habitat.—Central Pacific, Station 272, surface.
9. Staurosphæra andreæ, n. sp.
Shell thick walled, with regular, circular, hexagonally framed pores, three times as broad as the bars; nine to ten on the quadrant. From each hexagon-corner arises a bristle-shaped by-spine, half as long as the radius. Four main spines three-sided pyramidal, with spirally contorted edges, as long as the radius (very similar to Hexastylus solonis, Pl. 21, fig. 11, but with only four spines).
Dimensions.—Diameter of the shell 0.16, pores 0.01, bars 0.003.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
10. Staurosphæra thomæ.
Shell thick walled, with regular, circular pores, twice as broad as the bars; twelve to fourteen on the quadrant; surface covered with short conical by-spines. Four main spines conical, twice as long as the radius, twice as broad as one mesh.
Dimensions.—Diameter of the sphere 0.2, pores 0.012, bars 0.006.
Habitat.—South Atlantic, Station 332, depth, 2200 fathoms.
Definition.—Pores irregular, of different size or form; surface smooth.
11. Staurosphæra judæ, n. sp.
Shell thin walled, smooth, with irregular, polygonal pores, twice to four times as broad as the bars; six to ten on the quadrant. Four main spines three-sided pyramidal, as long as the radius.
Dimensions.—Diameter of the sphere 0.15, pores 0.006 to 0.012, bars 0.003.
Habitat.—Central Pacific, Station 273, depth, 2350 fathoms.
12. Staurosphæra crassa, Dunikowski.
Staurosphæra crassa, 1882, Denkschr. d. k. Akad. d. Wiss. Wien, Bd. xlv. p. 27, Taf. v. figs. 52-55.
Shell thick walled, smooth, with irregular, roundish pores, scarcely broader than the bars; eight to ten on the quadrant. Four spines three-sided pyramidal, nearly as long as the shell diameter.
Dimensions.—Diameter of the sphere 0.19, pores and bars 0.015.
Habitat.—Fossil in the Alpine Lias (Schafberg near Salzburg, Dunikowski).
13. Staurosphæra apostolorum, Haeckel.
? Cenosphæra megapora, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. iii. fig. 1.
? Cenosphæra micropora, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. iii. fig. 2.
Shell thin walled, smooth, with large, irregular, roundish pores, twice to six times as broad as the bars; four to six on the quadrant. Four spines conical, very stout, about as long as the shell diameter, often more or less irregularly disposed.
Dimensions.—Diameter of the sphere 0.12 to 0.2, pores 0.01 to 0.03, bars 0.005.
Habitat.—Fossil in Barbados.
Definition.—Pores irregular, of different size or form; surface covered with by-spines or accessory thorns.
14. Staurosphæra bartholomæi, n. sp.
Shell thin walled, with irregular, polygonal pores, three times as broad as the bars; six to eight on the quadrant; surface covered with short bristle-shaped by-spines. Four main spines three-sided pyramidal, twice as long as the radius.
Dimensions.—Diameter of the shell 0.14, pores 0.008 to 0.016, bars 0.003 to 0.005.
Habitat.—South Pacific, Station 285, depth 2375 fathoms.
15. Staurosphæra thaddæi, n. sp.
Shell thick walled, with irregular, roundish, polygonally framed pores, twice to three times as broad as the bars; five to seven on the quadrant; surface covered with bristle-shaped spines, half as long as the radius. Four main spines pyramidal, as long as the radius.
Dimensions.—Diameter of the shell 0.12, pores 006 to 0.012, bars 0.004.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms; also fossil in Barbados.
16. Staurosphæra matthæi, n. sp.
Shell thick walled, with irregular, roundish pores, twice to five times as broad as the bars; ten to twelve on the quadrant; surface covered with short conical thorns or by-spines. Four main spines conical, as long as the radius.
Dimensions.—Diameter of the shell 0.15, pores 0.004 to 0.01, bars 0.002.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
Definition.—Staurosphærida with one single lattice-sphere and four crossed spines which are arranged in opposite pairs, one pair opposite being larger than the other.
The genus Staurostylus has been developed from Staurosphæra by differentiation of the four crossed spines in pairs; two opposite spines growing much more strongly than the other two.
1. Staurostylus græcus, n. sp.
Shell thick walled, smooth, with regular, circular, hexagonally framed pores, twice as broad as the bars; six to eight on the quadrant. Spines three-sided prismatic, pointed, as broad as one mesh; two opposite larger spines as long as the diameter of the shell, two smaller only as long as the radius.
Dimensions.—Diameter of the shell 0.15, pores 0.01, bars 0.005; length of the major spines 0.16, minor 0.08.
Habitat.—Central Pacific, Station 274, depth 2750 fathoms.
2. Staurostylus latinus, n. sp.
Shell thin walled, smooth, with regular, circular, double-edged pores, three times as broad as the bars; twelve to fourteen on the quadrant. Spines conical, twice as broad at the base as one mesh; two opposite larger spines as long as the radius of the shell, two smaller only one-third as long.
Dimensions.—Diameter of the shell 0.24, pores 0.012, bars 0.004; length of the major spines 0.12, minor 0.04.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
3. Staurostylus germanicus, n. sp.
Shell thick walled, covered with bristle-shaped by-spines, half as long as the radius. Pores regular, circular, hexagonally framed, twice as broad as the bars; eight to ten on the quadrant. From each hexagon-corner arises one short by-spine. Four main spines three-sided pyramidal, as broad at the base as one mesh; two opposite larger spines one and a half times as long as the radius, two smaller two-thirds as long.
Dimensions.—Diameter of the shell 0.16, pores 0.008, bars 0.004; length of the major spines 0.12, minor 0.08.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
Definition.—Staurosphærida with one single lattice-sphere and four crossed spines, one of which is much larger than the other three.
The genus Stylostaurus differs from the preceding in the extraordinary development of one of the four spines, which is much longer than the other three; these may be equal or different.
1. Stylostaurus caudatus, n. sp. (Pl. 13, fig. 7).
Shell thick walled, smooth, with regular, circular, hexagonally framed pores, twice as broad as the bars; five to six on the quadrant. Spines three-sided pyramidal, as broad at the base as one mesh; one of the spines longer than the shell diameter, the opposite spine nearly as long as the shell radius; both lateral spines scarcely one-third as long.
Dimensions.—Diameter of the shell 0.1, pores 0.01, bars 0.005; length of the major spine 0.14, of the opposite 0.04, of both lateral spines 0.012.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
2. Stylostaurus gladiatus, n. sp.
Shell thick walled, smooth, with regular, circular pores, three times as broad as the bars; nine to ten on the quadrant. Spines three-sided prismatic, as broad at the base as one mesh; one of the spines longer than the shell diameter, and much larger than the other three, which are nearly equal (half as long as the radius).
Dimensions.—Diameter of the shell 0.2, pores 0.015, bars 0.005; length of the major spine 0.25, of the three others 0.005.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Definition.—Staurosphærida with two concentric spherical lattice-shells.
Definition.—Staurosphærida with two concentric lattice-spheres and four crossed, equal, simple spines.
The genus Staurolonche may be derived either from Staurosphæra by the duplication of the lattice-sphere, or from Carposphæra by the production of four crossed radial spines, lying in one meridional plane, or from Hexalonche by the reduction of two opposite spines.
Definition.—Pores of the cortical shell regular, and of nearly equal size and similar form; surface smooth.
1. Staurolonche hexagona, n. sp.
Haliomma hexagonum, Ehrenberg, 1854, Mikrogeol., Taf. xxxvb., Bd. iv. fig. 17.
Haliomma hexagonum, Haeckel, 1862, Monogr. d. Radiol., p. 434.
Cortical shell thin walled, smooth, three times as broad as the medullary shell, with regular, hexagonal pores, four times as broad as the bars; seven to eight on the quadrant. Four spines three-sided pyramidal, somewhat longer than the radius, as broad at the base as one mesh.
Dimensions.—Diameter of the outer shell 0.12, inner 0.04; cortical pores 0.012, bars 0.003; length of the spines 0.08.
Habitat.—North Atlantic, Station 64, depth 2700 fathoms.
2. Staurolonche spinozæ, n. sp.
Cortical shell thick walled, smooth, twice as broad as the medullary shell, with regular, circular, hexagonally framed pores, three times as broad as the bars; five to six on the quadrant. Four spines three-sided pyramidal, half as long as the radius, as broad at the base as one mesh.
Dimensions.—Diameter of the outer shell 0.16, inner 0.08; cortical pores 0.012, bars 0.004; length of the spines 0.04.
Habitat.—Central Pacific, Station 271, surface.
3. Staurolonche aperta, Haeckel.
Haliomma apertum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 74, Taf. xxviii. fig. 5.
Cortical shell thin walled, smooth, three times as broad as the medullary shell; pores regular, circular, five times as broad as the bars; four to five on the quadrant. Four spines conical, as long as the radius, as broad as one mesh.
Dimensions.—Diameter of the outer shell 0.1, inner 0.03; cortical pores 0.015, bars 0.003; length of the spines 0.05.
Habitat.—Fossil in Barbados.
4. Staurolonche brunonis, n. sp.
Cortical shell thick walled, smooth, twice as broad as the medullary shell, with regular, circular pores, three times as broad as the bars; eight to ten on the quadrant. Four spines cylindro-conical, longer than the diameter, twice as broad as one mesh.
Dimensions.—Diameter of the outer shell 0.08, inner 0.04; cortical pores 0.006, bars 0.002; length of the spines 0.12.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
5. Staurolonche pertusa, n. sp. (Pl. 15, figs. 5, 5a).
Cortical shell thin walled, smooth, three times as broad as the medullary shell, with regular, circular pores, three times as broad as the bars; eight to ten on the quadrant. Pores of the medullary shell only one-third as large, also circular. Four spines three-sided prismatic, three times as long as the radius; each of their three thin wings perforated by a single row of small pores.
Dimensions.—Diameter of the outer shell 0.1, inner 0.033; cortical pores 0.01, bars 0.003; length of the spines 0.15.
Habitat.—North Atlantic, Station 353, surface.
Definition.—Pores of the cortical shell regular, and of nearly equal size and similar form; surface covered with by-spines or thorns.
6. Staurolonche straussii, n. sp.
Cortical shell thin walled, four times as broad as the medullary shell, and covered with numerous bristle-shaped by-spines, half as long as the radius. Pores regular, circular, hexagonally framed, twice as broad as the bars; six to eight on the radius. On each hexagonal frame twelve by-spines (six at the corners, six in the middle between them). Four main spines six-sided pyramidal, about as long as the radius, twice as broad as one mesh.
Dimensions.—Diameter of the outer shell 0.16, inner 0.04; cortical pores 0.016, bars 0.008; length of the spines 0.1.
Habitat.—West Tropical Pacific, Station 225, depth 4475 fathoms.
7. Staurolonche feuerbachii, n. sp.
Cortical shell thick walled, five times as broad as the medullary shell, and covered with short conical by-spines. Pores regular, circular, twice as broad as the bars; twenty to twenty-two on the quadrant. Four main spines three-sided prismatic, with pyramidal apex, two to three times as long as the radius, twice as broad as one mesh.
Dimensions.—Diameter of the outer shell 0.27, of the inner 0.055; cortical pores 0.008, bars 0.004; length of the spines 0.3 to 0.4.
Habitat.—Fossil in Barbados.
8. Staurolonche moleschottii, n. sp.
Cortical shell thick walled, three times as broad as the medullary shell, and covered with short conical by-spines. Pores regular, circular, of the same breadth as the bars; fourteen to sixteen on the quadrant. Four main spines conical, as long as the radius, three times as broad at the base as one mesh.
Dimensions.—Diameter of the outer shell 0.15, inner 0.05; cortical pores and bars 0.004; length of the spines 0.08.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
Definition.—Pores of the cortical shell irregular, of different size or form; surface smooth.
9. Staurolonche holbachii, n. sp.
Cortical shell thin walled, with smooth surface, three times as broad as the medullary shell. Pores irregular, polygonal, twice to four times as broad as the bars. Four main spines three-sided prismatic, longer than the shell diameter.
Dimensions.—Diameter of the outer shell 0.12, inner 0.04; cortical pores 0.006 to 0.012, bars 0.003; length of the spines 0.15.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
10. Staurolonche gassendii, n. sp.
Cortical shell thick walled, with smooth surface, four times as broad as the medullary shell. Pores irregular, roundish, three to five times as broad as the bars. Four main spines conical, as long as the radius.
Dimensions.—Diameter of the outer shell 0.2, inner 0.05; cortical pores 0.01 to 0.02, bars 0.004; length of the spines 0.1.
Habitat.—North Atlantic, Station 353, depth 2965 fathoms.
Definition.—Pores of the cortical shell irregular, of different size or form; surface covered with by-spines or thorns.
11. Staurolonche epicurii, n. sp.
Cortical shell thick walled, five times as broad as the medullary shell, and covered with numerous bristle-shaped by-spines (half as long as the radius). Pores irregular, roundish, polygonally framed, twice to three times as broad as the bars. Four main spines pyramidal, as long as the radius.
Dimensions.—Diameter of the outer shell 0.22, inner 0.044; cortical pores 0.02 to 0.04, bars 0.012; length of the spines 0.1.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
12. Staurolonche lucretii, n. sp.
Cortical shell thick-walled, three times as broad as the medullary shell, and covered with numerous short, conical thorns. Pores irregular, roundish, twice to four times as broad as the bars. Four main spines conical, half as long as the radius.
Dimensions.—Diameter of the outer shell 0.15, inner 0.05; cortical pores 0.015 to 0.03, bars 0.008; length of the spines 0.04.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
Definition.—Staurosphærida with two concentric lattice-spheres and four crossed, equal, branched spines.
The genus Staurancistra differs from its ancestral form, Staurolonche, in the ramification of the four crossed spines.
1. Staurancistra quadricuspis, n. sp.
Cortical shell thin walled, with rough, thorny surface, and irregular, roundish pores, twice to four times as broad as the bars; six to eight on the quadrant. Medullary shell one-third as large, with regular, circular pores; connected with the cortical shell by four crossed radial beams. These are prolonged outside into four strong three-sided prismatic spines, nearly as long as the shell diameter, each having three curved branches below the distal end. (Similar to Hexancistra quadricuspis, Pl. 22, fig. 11, but with only four spines.)
Dimensions.—Diameter of the cortical shell 0.16, of the medullary shell 0.05; pores of the former 0.06 to 0.012, bars 0.003; length of the spines 0.14, breadth 0.012.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Definition.—Staurosphærida with two concentric lattice-spheres and four crossed simple spines which are disposed in two different pairs, two opposite being larger than the other two.
The genus Staurolonchidium has arisen from Staurolonche by the stronger growth of the two opposite spines, the other two remaining stationary; both spines of each pair equal.
1. Staurolonchidium artioscelides, n. sp.
Cortical shell thin walled, with smooth surface, three times as broad as the medullary shell. Pores regular, circular, hexagonally framed, twice as broad as the bars; eight to ten on the quadrant. Four radial spines three-sided pyramidal, as broad as one mesh; two opposite larger spines three times as long as the two smaller, which are about equal to the radius.
Dimensions.—Diameter of the cortical shell 0.16, medullary shell 0.05; pores of the former 0.012, bars 0.006; length of the major spines 0.24, minor 0.08.
Habitat.—Central Pacific, Station 265, surface.
2. Staurolonchidium perspicuum, Haeckel.
Haliomma perspicuum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 74, Taf. xxix. fig. 1.
Cortical shell thin walled, covered with small conical by-spines, five times as broad as the medullary shell. Pores regular, circular, eight times as broad as the bars; three to four on the quadrant. Four radial spines three-sided pyramidal, scarcely one-third as broad as one mesh; two opposite larger spines four times as long as the two smaller, which are about equal to half the radius.
Dimensions.—Diameter of the cortical shell 0.12, medullary shell 0.025; pores of the former 0.03, bars 0.004; length of the major spines 0.12, minor 0.03.
Habitat.—Fossil in Barbados.
Definition.—Staurosphærida with two concentric lattice-spheres and four crossed simple spines, one of which is much larger than the other three.
The genus Stauroxiphos differs from its ancestral form, Staurolonche, in the greater development of one single spine, and exhibits therefore the same relation to it that Stylostaurus bears to Staurosphæra.
1. Stauroxiphos gladius, n. sp. (Pl. 15, fig. 7).
Cortical shell thick walled, smooth, three times as broad as the medullary shell. Pores of the outer shell regular, circular, regularly six-lobed on the outer opening, four times as broad as the bars; about six on the quadrant. Pores of the inner shell only one-third as large, simple, circular. Three of the four radial spines of nearly equal size, pommel-shaped, with three prominent, dentated wings, somewhat shorter than the shell radius and about half as broad as long; the fourth spine much larger, sword-like, about three times as long as the shell radius.
Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04; pores of the former 0.01, bars 0.0025; pores of the latter 0.003, bars 0.001; length of the major spine 0.18, of the three minor 0.04.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
Definition.—Staurosphærida with three concentric spherical lattice-shells.
Definition.—Staurosphærida with three concentric lattice-spheres and four crossed, equal, simple spines.
The genus Stauracontium differs from its probable ancestral form, Staurolonche, in the duplication of the cortical shell.
Definition.—Pores of the cortical shell regular, all of nearly equal size and similar form; surface smooth.
1. Stauracontium cruciferum, n. sp.
Cortical shell thin walled, smooth, with regular, hexagonal pores, four times as broad as the bars; eight to ten on the quadrant. Radial proportion of the three spheres = 1 : 3 : 9. Connecting radial beams between them six (opposite in pairs in the three dimensive axes), but only four of them are prolonged outside into four stout three-sided prismatic spines, lying in one equatorial plane, as long as the shell diameter.
Dimensions.—Diameter of the outer shell 0.22, middle 0.07, inner 0.025; cortical pores 0.012, bars 0.003; length of the spines 0.2.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
2. Stauracontium tetracanthum, Haeckel.
Haliomma tetracanthum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 295, Taf. x. figs. 7, 8.
Cortical shell thin walled, smooth, with regular, circular pores, three times as broad as the bars; five to six on the quadrant. Radial proportion of the three spheres = 1 : 3 : 12. Radial spines three-sided pyramidal, about as long as the shell diameter.
Dimensions.—Diameter of the outer shell 0.12, middle 0.03, inner 0.01; cortical pores 0.01, bars 0.003; length of the spines 0.1.
Habitat.—Indian Ocean, Zanzibar, depth 2200 fathoms, Pullen.
3. Stauracontium tetracontium, Haeckel.
Actinomma tetracanthum, Stöhr, 1880, Palæontogr. 26, p. 91, Taf. ii. fig. 6.
Cortical shell thin walled, rough, with regular, circular pores, of the same breadth as the bars; six to seven on the quadrant. Radial proportion of the three spheres = 1 : 2.5 : 8. Radial spines three-sided pyramidal, nearly as long as the shell diameter.
Dimensions.—Diameter of the outer shell 0.1, middle 0.03, inner 0.013; cortical pores and bars 0.006; length of the spines 0.08.
Habitat.—Fossil in Tertiary rocks of Sicily; Grotte, Caltanisetta.
Definition.—Pores of the cortical shell regular, and of nearly equal size and similar form; surface covered with numerous small thorns or by-spines.
4. Stauracontium daturæforme, Haeckel.
Actinomma daturæforme, Stöhr, 1880, Palæontogr. 26, p. 93, Taf. ii. fig. 13.
Cortical shell thick walled, covered with short thorns, and with regular, hexagonal pores, five times as broad as the bars; six to seven on the quadrant. Radial proportion of the three spheres = 1 : 3 : 3.5. Radial spines six-sided pyramidal, about half as long as the radius and one-fourth as broad.
Dimensions.—Diameter of the outer shell 0.15, middle 0.13, inner 0.04; cortical pores 0.017, bars 0.003; length of the spines 0.03.
Habitat.—Fossil in Tertiary rocks of Sicily; Grotte, Stöhr.
5. Stauracontium sparganium, n. sp.
Cortical shell thick walled, covered with very numerous, short, conical spines, and with regular, circular pores, five times as broad as the bars; sixteen to eighteen on the quadrant. Radial proportion of the three spheres = 2 : 3 : 9. Radial main spines three-sided prismatic, as long as the radius or longer.
Dimensions.—Diameter of the outer shell 0.275, middle 0.09, inner 0.06; cortical pores 0.01, bars 0.002; length of the spines 0.15.
Habitat.—Fossil in Barbados.
Definition.—Pores irregular, of different size or form; surface smooth.
6. Stauracontium antarcticum, n. sp.
Cortical shell thin walled, smooth. Pores irregular, roundish, two to four times as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 8. Radial spines conical, as long as the radius.
Dimensions.—Diameter of the outer shell 0.2, middle 0.05, inner 0.025; cortical pores 0.006 to 0.012, bars 0.003; length of the spines 0.1.
Habitat.—Antarctic Ocean, Station 157, depth 1950 fathoms.
Definition.—Pores irregular, of different size or form; surface covered with thorns or by-spines.
7. Stauracontium setosum, n. sp.
Cortical shell thin walled, covered with thin bristle-shaped by-spines, half as long as the radius. Pores irregular, polygonal, three to five times as broad as the bars. Proportion of the three spheres = 1 : 2 : 6. Radial main spines pyramidal, nearly as long as the shell diameter.
Dimensions.—Diameter of the outer shell 0.15, middle 0.05, inner 0.025; cortical pores 0.01 to 0.015, bars 0.003; length of the spines 0.12.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
8. Stauracontium papillosum, n. sp.
Cortical shell thick walled, covered with short conical papillæ or by-spines. Pores irregular, roundish, two to four times as broad as the bars. Proportion of the three spheres = 1 : 3 : 12. Radial main spines conical, as long as the radius.
Dimensions.—Diameter of the outer shell 0.24, middle 0.06, inner 0.02; cortical pores 0.007 to 0.015, bars 0.004; length of the spines 0.12.
Habitat.—Central Pacific, Station 274, depth 2750 fathoms.
Definition.—Staurosphærida with four concentric spherical lattice-shells.
Definition.—Staurosphærida with four concentric lattice-spheres and four crossed, equal, simple spines.
The genus Staurocromyum has arisen probably from Stauracontium by duplication of the cortical shell, two concentric shells lying within, two others outside the central capsule.
1. Staurocromyum quadruplex, n. sp.
Radial proportion of the four spheres = 1 : 2 : 8 : 10. Both medullary shells with very small, regular, circular pores. Inner cortical shell with regular, circular, hexagonally-framed pores, twice as broad as the bars; from each hexagon-corner arises a small by-spine, and these, connected by tangential branches at equal distances from the centre, form the delicate outer cortical shell, with spiny surface. Four main spines three-sided pyramidal, as long as the shell radius.
Dimensions.—Diameter of the four shells—(A) 0.25, (B) 0.2, (C) 0.05, (D) 0.025; length of the spines 0.12.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
2. Staurocromyum quadrispinum, n. sp.
Radial proportion of the four spheres = 1 : 3 : 9 : 12. Both medullary shells with small, regular, circular pores. Both cortical shells with irregular, roundish pores. Surface covered with short, conical by-spines. Four main spines cylindro-conical, somewhat longer than the shell diameter.
Dimensions.—Diameter of the four shells—(A) 0.24, (B) 0.18, (C) 0.06, (D) 0.02.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
Definition.—Staurosphærida with four concentric lattice-spheres and four crossed, equal, branched spines.
The genus Cromyostaurus differs from the preceding Staurocromyum, its ancestral form, in the ramification of the four crossed spines.
1. Cromyostaurus verticillatus, n. sp.
Radial proportion of the four spheres = 1 : 3 : 11 : 13. Both medullary shells with small, regular, circular pores; inner cortical shell with regular, hexagonal pores; from the hexagon-corners arise small, radial by-spines, which at equal distances from the centre send out forked tangential branches, three from each spine, and by communication of these form the outer, delicate, cortical shell. Four main spines nearly as long as the shell diameter, three-sided prismatic, with four to six verticils of ramified lateral branches, each verticil composed of three forked branches, which ramify again.
Dimensions.—Diameter of the four shells—(A) 0.26, (B) 0.22, (C) 0.06, (D) 0.02; length of the spines 0.24.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
Definition.—Staurosphærida with five or more concentric spherical lattice-shells.
Definition.—Staurosphærida with five or more concentric lattice-spheres and four crossed, equal spines.
The genus Staurocaryum has arisen from the preceding Staurocromyum by the further multiplication of the concentric spheres; in the only observed form there are six, at nearly equal distances apart.
1. Staurocaryum arborescens, n. sp. (Pl. 15, fig. 8).
Shell composed of six concentric latticed spheres, at nearly equal distances apart, and with somewhat regular, circular pores, the size of which gradually increases from the first to the sixth shell. The surface of the outermost shell is densely covered with numerous arborescent by-spines, which bifurcate from three to four times, and are three-sided pyramidal at the base, and twice as long as the distance between each two shells. The six shells are connected only by four crossed, conical, radial beams, which increase in diameter from the centre, and are prolonged outside into very stout cylindrical, radial spines, irregularly covered with small thorns and forked ramules, and nearly as long as the shell diameter. Only a single specimen was observed.