Legion I. SPUMELLARIA, (continued 6)

Habitat.—North Pacific, Station 253, surface.

23. Acanthosphæra brevispina, n. sp.

Shell thick walled, with irregular polygonal meshes, twice to four times as broad as the bars; twelve to sixteen on the radius. Sixty to eighty radial spines, pyramidal, half as long as the radius of the shell, one-fourth as broad at the base.

Dimensions.—Diameter of the shell 0.2 to 0.22, pores 0.006 to 0.012, bars 0.003; length of the spines 0.05, basal breadth 0.02.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

24. Acanthosphæra acanthica, Haeckel.

Cenosphæra acanthica, Stöhr, 1880, Palæontogr., vol. xxvi. p. 86, Taf. i. fig. 3.

Shell thick walled, with irregular, roundish pores, twice to three times as broad as the bars; seven to nine on the radius. Ten to twenty radial spines pyramidal, shorter than the radius, twice as broad at the base as one mesh.

Dimensions.—Diameter of the shell 0.12 to 0.16, pores 0.006 to 0.009, bars 0.003; length of the spines 0.04 to 0.06, basal breadth 0.01 to 0.015.

Habitat.—Fossil in Tertiary rocks of Sicily and Barbados.

25. Acanthosphæra haliphormis, Ehrenberg.

Acanthosphæra haliphormis, Ehrenberg, 1861, Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, Taf. ii. fig. 1.

Shell thick walled, with irregular, roundish pores, twice to four times as broad as the bars; four to five on the radius. Twelve to twenty radial spines pyramidal, longer than the radius, scarcely as broad as one mesh at the base.

Dimensions.—Diameter of the shell 0.11, pores 0.01 to 0.02, bars 0.005; length of the spines 0.06 to 0.08, basal breadth 0.01.

Habitat.—Arctic Ocean, near Greenland, depth 1000 fathoms.

26. Acanthosphæra angulata, n. sp. (Pl. 26, fig. 4).

Shell thin walled; its pores irregular, roundish, with angular, double-edged margin, two to four times as broad as the bars; six to eight on the radius. Twenty to thirty radial spines pyramidal, angular, with prominent edges, shorter than the radius, as broad at the base as one small mesh.

Dimensions.—Diameter of the shell 0.2, pores 0.02 to 0.04, bars 0.01; length of the spines 0.06, basal breadth 0.02.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

27. Acanthosphæra conifera, n. sp.

Shell thick walled, with irregular, roundish pores, twice to five times as broad as the bars; ten to twelve on the radius. Twenty radial spines conical, regularly disposed, half as long as the radius, as broad at the base as one of the largest meshes.

Dimensions.—Diameter of the shell 0.2, pores 0.008 to 0.02, bars 0.004; length of the spines 0.05, basal breadth 0.02.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

28. Acanthosphæra maxima, n. sp.

Shell thick walled, with irregular, roundish pores, twice to eight times as broad as the bars; twelve to twenty on the radius. Radial spines very numerous (two to three hundred), short, conical, scarcely as long as the diameter of the largest meshes, and one-third as broad.

Dimensions.—Diameter of the shell 0.3 to 0.4, pores 0.008 to 0.03, bars 0.004; length of the radial spines 0.03, basal breadth 0.01.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

29. Acanthosphæra simplex, Haeckel.

Rhaphidococcus simplex, Haeckel, Monogr. d. Radiol., 1862, p. 366, figs. 5, 6.Taf. xiii.

Cladococcus simplex, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 800.

Shell thick walled, with irregular, roundish pores, three to six times as broad as the bars; eight to nine on the radius. Forty to sixty radial spines, about as long as the diameter of the shell, three-sided prismatic, not straight, but more or less bent.

Dimensions.—Diameter of the shell 0.12, pores 0.005 to 0.012, bars 0.0015 to 0.02; length of the spines 0.12, breadth 0.003.

Habitat.—Mediterranean (Messina), surface, Haeckel.

30. Acanthosphæra gibbosa, n. sp.

Shell thin walled, rugged or tuberculate, covered by about twenty hill-shaped tubercles or protuberances with flat valleys between them. Network very delicate, with thread-like bars and irregular, polygonal pores; twenty to thirty on the radius. Radial spines very numerous, bristle-shaped, twice to three times as long as the diameter of the pores.

Dimensions.—Diameter of the shell 0.3, pores 0.01 to 0.02; length of the spines 0.02 to 0.05.

Habitat.—Central Pacific, Station 274, surface.

31. Acanthosphæra reticulata, n. sp. (Pl. 26, fig. 5).

Rhaphidosphæra reticulata, Haeckel, 1881, Prodromus.

Shell thick walled, with irregular, roundish pores, twice to four times as broad as the bars; six to eight on the radius. Surface of the bars covered with a peculiar delicate network of very fine crests. Twenty to forty radial spines, angular, pyramidal, scarcely one-third as long as the radius of the shell, as broad at the base as the bars.

Dimensions.—Diameter of the shell 0.22, pores 0.02 to 0.04, bars 0.01; length of the spines 0.04, basal breadth 0.01.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Genus 89. Heliosphæra,^[123] Haeckel, 1862, Monogr. d. Radiol., p. 350 (sensu emendato).

Definition.—Astrosphærida with one simple lattice-sphere, covered with simple radial spines of two different kinds: larger main spines and smaller by-spines.

The genus Heliosphæra (in the mended definition here employed) differs from the foregoing Acanthosphæra in the possession of two different kinds of radial spines: larger main spines scattered on the surface or disposed regularly in limited numbers (twelve to twenty, sometimes forty to fifty or more), and smaller by-spines in much larger numbers, arising from all the nodal-points of the network (or sometimes also from its bars).

Subgenus 1. Heliosphærella, Haeckel.

Definition.—Pores of the shell regular or subregular, all of nearly equal size and similar form.

1. Heliosphæra hexagonaria, n. sp. (Pl. 26, fig. 2).

Shell very thin walled, about twenty times as broad as one pore. Meshes or pores subregular, hexagonal, with thread-like bars; fifteen to seventeen on the radius. Radial spines at the nodal-points of the network; about forty main spines three-sided pyramidal, half as broad at the base as one pore, and twice as long as the bristle-shaped by-spines, which are very numerous, and as long as the diameter of one pore.

Dimensions.—Diameter of the shell 0.25 to 0.3, of the meshes or pores 0.012 to 0.015, bars below 0.001; length of the main spines 0.03, basal breadth 0.007.

Habitat.—Central Pacific, Stations 272 to 274, depth 2350 to 2750 fathoms.

2. Heliosphæra actinota, Haeckel.

Heliosphæra actinota, Haeckel, 1862, Monogr. d. Radiol., p. 352, Taf. ix. fig. 3.

Shell very thin walled, about ten times as broad as one mesh. Pores regular, hexagonal, with thread-like bars; six to eight on the radius. Radial spines at the nodal-points of the network, bristle-shaped, scarcely broader than the bars; about twenty main spines as long as the diameter of the shell, and numerous by-spines, only one-third to one-half as long as the former.

Dimensions.—Diameter of the shell 0.2 to 0.25, of the meshes 0.02 to 0.03, bars below 0.001; length of the main spines 0.2 to 0.3.

Habitat.—Mediterranean (Messina), Atlantic (Canaries, Azores), surface.

3. Heliosphæra echinoides, Haeckel.

Heliosphæra echinoides, Haeckel, 1862, Monogr. d. Radiol., p. 352, Taf. ix. fig. 4.

Shell thin walled, about six times as broad as one mesh. Pores regular, hexagonal, eight times as broad as the bars. Radial spines arising, not from the nodal-points of the network, but from the midst of the bars (very rare disposition!); twenty main spines regularly disposed, as long as the radius, four times as long as the numerous by-spines; all spines bristle-shaped, of the same breadth as the bars.

Dimensions.—Diameter of the shell 0.09, pores 0.015, bars 0.002; length of the main spines 0.04.

Habitat.—Mediterranean (Messina), surface, Haeckel.

4. Heliosphæra elegans, Haeckel.

Heliosphæra elegans, Haeckel, 1862, Monogr. d. Radiol., p. 353, Taf. ix. fig. 5.

Shell very thin walled, about ten times as broad as one mesh. Pores regular, hexagonal, with thread-like bars, which are crossed by tangential bars, so that each side of a hexagon exhibits a regular rectangular cross (exactly the same as in Pl. 19, fig. 5). All radial spines bristle-shaped, as thin as the bars, and arising from the nodal-points; twenty main spines as long as the radius, numerous by-spines scarcely one-sixth as long.

Dimensions.—Diameter of the shell 0.26, pores 0.026, bars below 0.001; length of the main spines 0.13.

Habitat.—Mediterranean (Messina), surface, Haeckel.

5. Heliosphæra pectinata, n. sp. (Pl. 26, fig. 9).

Acanthosphæra pectinata, Haeckel, 1881, Atlas.

Shell thick walled, combed, about fourteen times as broad as one mesh. Pores subregular, circular, with elevated hexagonal frames, three times as broad as the bars. Radial spines very 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).

Acanthosphæra coronata, Haeckel, 1881, Atlas.

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, twice as broad at the base as one pore. (Very similar to some species of Castanella, Pl. 113, but without the osculum characteristic of this Phæodarian; may be easily confounded with it.)

Dimensions.—Diameter of the shell 0.3, pores 0.015, bars 0.015; length of the main spines 0.25, basal breadth 0.03.

Habitat.—North Pacific (Japan), Station 234, surface.

Subgenus 2. Heliosphæromma, Haeckel.

Definition.—Pores of the shell irregular, of different size or form.

10. Heliosphæra polygonaria, n. sp.

Shell very thin walled, with thread-like bars and irregular, polygonal pores (having four to eight angles, commonly five to seven); eight to ten on the radius. Radial spines at all the nodal-points of the network, bristle-shaped; forty to sixty main spines, as long as the radius, twice as thick as the numerous by-spines, which are not larger than one mesh.

Dimensions.—Diameter of the shell 0.15 to 0.2, pores 0.012 to 0.02, bars 0.001; length of the main spines 0.08 to 0.1.

Habitat.—Central Pacific, Stations 266 to 272, surface.

11. Heliosphæra heteracantha, n. sp.

Shell thin walled, with irregular, polygonal pores, twice to four times as broad as the bars; six to eight on the radius. Twenty radial main spines, three-sided pyramidal, nearly as long as the diameter of the shell, as broad as a larger mesh; innumerable bristle-shaped by-spines variously distributed on the bars and at the nodal-points of the net; half as long as the radius.

Dimensions.—Diameter of the shell 0.12, pores 0.006 to 0.012, bars 0.003; length of the main spines 0.1, basal breadth 0.012.

Habitat.—Equatorial Atlantic, Station 347, surface.

12. Heliosphæra hyperionis, n. sp.

Shell thick walled. Pores irregular, roundish, with polygonal frames, three to six times as broad as the bars; twelve to fourteen on the radius. Thirty to forty main spines, angular, pyramidal, scarcely as long as the radius and twice as long as the numerous bristle-shaped by-spines.

Dimensions.—Diameter of the shell 0.24, pores 0.006 to 0.012, bars 0.002; length of the main spines 0.1, basal breadth 0.012.

Habitat.—North Pacific, Station 256, surface.

13. Heliosphæra elector, n. sp.

Shell thick walled, with irregular, roundish pores, twice to three times as broad as the bars; eight to ten on the radius. Twenty main spines, three-sided pyramidal, somewhat longer than the radius and four times as long as the short bristle-shaped by-spines.

Dimensions.—Diameter of the shell 0.12, pores 0.005 to 0.01, bars 0.003; length of the main spines 0.08, basal breadth 0.01.

Habitat.—South Atlantic, Station 325, surface.

14. Heliosphæra solaris, n. sp.

Shell thick walled, with irregular, roundish pores, about the same breadth as the bars; six to eight on the radius. Fifty to eighty main spines, conical, as long as the radius; by-spines very numerous, also conical, but only as large as one pore.

Dimensions.—Diameter of the shell 0.15, pores and bars 0.006 to 0.008; length of the main spines 0.08, basal breadth 0.012.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

Genus 90. Conosphæra,^[124] Haeckel, 1881, Prodromus, p. 451.

Definition.—Astrosphærida with one simple latticed sphere, covered with radial spines having the form of hollow cones with porous walls.

The genus Conosphæra differs from Acanthosphæra in the peculiar formation of the radial spines, which are not simple solid sticks, but hollow cones with porous walls, as immediate elevations of the hollow sphere.

1. Conosphæra platyconus, n. sp.

Pores of the shell regular, circular, twice as broad as the bars; ten to twelve on the radius. Conical spines about sixty, regular, broader than they are high, with six to nine pores in the wall.

Dimensions.—Diameter of the shell 0.16, pores 0.008, bars 0.004; length of the spines 0.012, basal breadth 0.024.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

2. Conosphæra orthoconus, n. sp. (Pl. 12, fig. 2).

Pores of the shell irregular, roundish, twice to three times as broad as the bars; fourteen to sixteen on the radius. Conical spines about forty, regular, higher than they are broad, as long as the radius, with sixteen to twenty pores in the wall.

Dimensions.—Diameter of the shell 0.2, pores 0.008 to 0.012, bars 0.004; length of the spines 0.05, basal breadth 0.03.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

3. Conosphæra plagioconus, n. sp. (Pl. 12, fig. 4).

Pores of the shell irregular, polygonal, twice to five times as broad as the bars; twenty to twenty-four on the radius. Conical spines about eighty, irregularly formed and scattered, with oblique (not radial) axes; about as high as broad, with eight to twelve pores in the wall.

Dimensions.—Diameter of the shell 0.25, pores 0.005 to 0.015, bars 0.003; length of the spines 0.02, basal breadth 0.02.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Genus 91. Coscinomma,^[125] n. gen.

Definition.—Astrosphærida with one simple lattice-sphere, covered with simple radial spines; the pores between them prolonged into hollow, conical, or cylindrical tubuli.

The genus Coscinomma exhibits among the Astrosphærida the same peculiar formation that distinguishes Ethmosphæra and Sethosphæra among the Liosphærida; each pore of the simple shell is prolonged into a short conical or cylindrical tubulus, as a rule either on the outside or on the inside of the shell, but sometimes on both sides.

Subgenus 1. Coscinommarium, Haeckel.

Definition.—Pores prolonged into short tubes both on the inside as well as the outside of the shell.

1. Coscinomma amphisiphon, Haeckel (Pl. 26, figs. 1, 1a, 1b).

Pores regular, circular, hexagonally framed, twice as broad as the bars, prolonged on the inside as well as on the outside of the shell into a short truncated conical tube; fifteen to eighteen pores on the radius. In each hexagon-corner arises a bristle-shaped radial spine, half as long as the radius.

Dimensions.—Diameter of the shell 0.22, pores 0.01, bars 0.005; length of the spines 0.1.

Habitat.—Central Pacific, Station 271, surface.

Subgenus 2. Coscinommidium, Haeckel.

Definition.—Pores prolonged into external tubes on the outside of the shell.

2. Coscinomma ectosiphon, n. sp.

Pores regular, circular, hexagonally framed, twice as broad as the bars, prolonged on the outside of the shell into a short truncated conical tube; ten to twelve pores on the radius. In each hexagon-corner arises a short bristle-shaped spine, twice as long as the tube, one-third as long as the radius. (Very similar to Ethmosphæra conulosa, Pl. 12, fig. 5, but differs in the possession of radial spines.)

Dimensions.—Diameter of the shell 0.2, pores 0.012, bars 0.006; length of the spines 0.04, of the tubes 0.02.

Habitat.—North Pacific, Station 253, surface.

3. Coscinomma macrosiphon, n. sp.

Pores regular, circular, without hexagonal frames, of the same breadth as the bars, prolonged on the outside of the shell into a long cylindrical tube, half as long as the radius (eight to nine pores on the radius); between them bristle-shaped, at the base conical, radial spines of double length.

Dimensions.—Diameter of the shell 0.16, pores and bars 0.008; length of the spines 0.08, of the tubes 0.04.

Habitat.—Central Pacific, Station 274, surface.

Subgenus 3. Coscinommonium, Haeckel.

Definition.—Pores prolonged into internal tubes on the inside of the shell.

4. Coscinomma endosiphon, n. sp.

Pores regular, circular, hexagonally framed, twice as broad as the bars (fourteen to sixteen on the radius), prolonged on the inside of the shell into a short truncated cylindrical tube. In each hexagon-corner arises a thin, bristle-shaped, radial spine with pyramidal base, half as long as the radius, twice as long as the tube.

Dimensions.—Diameter of the shell 0.25, pores 0.012, bars 0.006; length of the spines 0.066, of the tubes 0.03.

Habitat.—South Pacific, Station 288, surface.

Genus 92. Cladococcus,^[126] J. Müller, 1856, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 485.

Definition.—Astrosphærida with one simple lattice-sphere, covered with branched radial spines (the stem of the spine never forked).

The genus Cladococcus, together with the following Elaphococcus, is distinguished from the other Coscinommida by the ramification of the radial spines covering the surface of the simple hollow lattice-sphere. In Cladococcus each spine sends out three or more lateral branches, which are either simple or again ramified; but the stem of the spine itself is not forked, as in Elaphococcus.

Subgenus 1. Cladococcalis, Haeckel.

Definition.—Branches of the spines simple, not ramified. Pores regular, all of nearly equal size and similar form.

1. Cladococcus arborescens, J. Müller.

Cladococcus arborescens, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 31, Taf. i. fig. 2.

Pores of the spherical shell regular, hexagonal, three times as broad as the bars; three to four on the radius. Ten to twenty spines, three-sided prismatic, two to three times as long as the shell diameter; towards the distal end each spine with three branches (one lateral simple straight branch on each edge of the spine).

Dimensions.—Diameter of the shell 0.1, pores 0.012, bars 0.004; length of the spines 0.2 to 0.3, breadth 0.02.

Habitat.—Mediterranean (Nice); North Atlantic, Canary Islands, surface.

2. Cladococcus spinifer, Haeckel.

Cladococcus spinifer, Haeckel, 1862, Monogr. d. Radiol., p. 368, Taf. xiii. fig. 9.

Pores regular, circular, hexagonally framed, three times as broad as the bars; five to six on the radius. Radial spines, arising from all the nodal-points of the network, three-sided, longer than the shell diameter, with six to twelve simple verticillate branches (two to four branches on each edge).

Dimensions.—Diameter of the shell 0.08, pores 0.01, bars 0.003; length of the spines 0.1, breadth 0.03.

Habitat.—Mediterranean (Messina), surface.

3. Cladococcus penicillus, n. sp.

Pores subregular, hexagonal, twice as broad as the bars; eight to ten on the radius. Sixty to eighty radial spines, three-sided prismatic, pencil-shaped, longer than the shell diameter; each at the distal end with a brush or pencil composed of nine to twenty-one short, simple, curved branches (three to seven on each edge).

Dimensions.—Diameter of the shell 0.1, pores 0.006, bars 0.003; length of the spines 0.12 to 0.16, breadth 0.006.

Habitat.—Central Pacific, Station 271, surface.

Subgenus 2. Cladococcinus, Haeckel.

Definition.—Branches of the spines simple, not ramified. Pores irregular, of different size or form.

4. Cladococcus antarcticus, n. sp.

Pores irregular, polygonal, twice to four times as broad as the bars; five to six on the radius. Forty to fifty radial spines, angular, curved, of variable size and form, with three to nine irregular, simple, blunt curved branches.

Dimensions.—Diameter of the shell 0.14, pores 0.01 to 0.02, bars 0.05; length of the spines 0.1 to 0.18, breadth 0.007.

Habitat.—Antarctic Ocean, Station 157, depth 1950 fathoms.

5. Cladococcus japonicus, n. sp.

Pores irregular, roundish, of the same breadth as the bars; six to eight on the radius. Twenty to thirty radial spines, angular, longer than the shell diameter, with thirty to forty simple branches, decreasing in size from the middle part of the spine to the distal end (ten to thirteen branches on each edge).

Dimensions.—Diameter of the shell 0.12, pores and bars 0.007; length of the spines 0.15 to 0.2, breadth 0.004.

Habitat.—North Pacific (Japan), Station 240, surface.

6. Cladococcus quadricuspis, n. sp.

Pores irregular, roundish, twice to eight times as broad as the bars; eight to ten on the radius. About twenty radial spines, three-sided prismatic, as long as the shell diameter; in the proximal half simple, with smooth edges; in the distal half with three diverging simple branches, half the length of the spine, with dentated edges.

Dimensions.—Diameter of the shell 0.15, pores 0.004 to 0.016, bars 0.002; length of the spines 0.17, breadth 0.01.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Subgenus 3. Cladococcodes, Haeckel.

Definition.—Branches of the spines again ramified. Pores regular, of nearly equal size and similar form.

7. Cladococcus scoparius, n. sp. (Pl. 27, fig. 2).

Pores regular, circular, three times as broad as the bars; five to six on the radius. Twenty radial spines, broom-shaped, three times as long as the shell diameter; in the proximal half simple, in the distal half branched, with three to nine branches, which are again ramified; spines and their branches with three smooth edges, not dentated.

Dimensions.—Diameter of the shell 0.055, pores 0.0075, bars 0.0025; length of the spines 0.15, basal thickness 0.007.

Habitat.—Central Pacific, Station 271, surface.

8. Cladococcus viminalis, Haeckel.

Cladococcus viminalis, Haeckel, 1862, Monogr. d. Radiol., p. 369, Taf. xiv. figs. 2, 3.

Pores regular, circular, hexagonally framed, four times as broad as the bars; five to six on the radius. Radial spines, arising from all the nodal-points of the network, twice as long as the shell diameter; in the basal half simple, in the distal half with three to six long, thin, curved branches, which are partly forked; three edges of the spines dentated.

Dimensions.—Diameter of the shell 0.08, pores 0.01, bars 0.003; length of the radial spines 0.16, basal breadth 0.003.

Habitat.—Mediterranean (Messina).

9. Cladococcus bifurcus, Haeckel.

Cladococcus bifurcus, Haeckel, 1862, Monogr. d. Radiol., p. 368, Taf. xiii. figs. 7, 8.

Pores regular, circular, hexagonally framed, four times as broad as the bars; five to seven on the radius. Radial spines arising from all the nodal-points, three-sided prismatic, with dentated edges, longer than the shell diameter. On each spine six to nine branches, which are for the most part forked, the distal branches only being simple. (May be regarded as a further developmental stage of Cladococcus spinifer and Cladococcus viminalis.)

Dimensions.—Diameter of the shell 0.08, pores 0.01, bars 0.0025; length of the spines 0.1, basal breadth 0.003.

Habitat.—Mediterranean (Messina), Canary Islands, Azores, surface.

10. Cladococcus pinetum, n. sp. (Pl. 27, fig. 1).

Pores regular, circular, polygonally framed, about the same breadth as the bars: two to three on the radius. About twenty radial spines, very large, three to four times as long as the shell diameter, branched like a pine tree, with straight, stout, three-sided prismatic stem; three prominent edges dentated. On each edge five to seven lateral branches, the distal ends of which are simple, the proximal again ramified, with numerous ramules. The figured specimen is a young one, with branches but little developed.

Dimensions.—Diameter of the shell 0.06, pores and bars 0.008; length of the spines 0.2 to 0.25 breadth 0.01.

Habitat.—Central Pacific, Station 266 to 274, surface.

Subgenus 4. Cladococcurus, Haeckel.

Definition.—Branches of the spines again ramified. Pores irregular, of different size and form.

11. Cladococcus abietinus, n. sp. (Pl. 27, fig. 3).

Pores irregular, roundish, twice to four times as broad as the bars; six to ten on the radius. About twenty radial spines, two to three times as long as the shell diameter, branched like a pine tree, with straight, stout, three-sided pyramidal stem. From the dentated edges arise numerous verticillate branches, the proximal ends of which are thickly ramified. (Differs from the preceding and similar species mainly in the large size and irregular lattice-work of the shell.)

Dimensions.—Diameter of the shell 0.12 to 0.14, pores 0.006 to 0.012, bars 0.003; length of the spines 0.25 to 0.4, breadth 0.012.

Habitat.—North Pacific, Station 256, surface.

12. Cladococcus tricladus, n. sp.

Pores irregular, polygonal, twice to eight times as broad as the bars; eight to ten on the radius. About twenty radial spines, three-sided prismatic, twice as long as the shell diameter; in the proximal half simple, with smooth edges; in the distal half with three diverging curved branches, which bifurcate two to three times or ramify irregularly. (Closely related to the simpler Cladococcus quadricuspis.)

Dimensions.—Diameter of the shell 0.16, pores 0.04 to 0.016, bars 0.002; length of the spines 0.3, breadth 0.012.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

13. Cladococcus stalactites, n. sp. (Pl. 27, fig. 4).

Pores irregular, roundish, once to five times as broad as the bars; eight to ten on the radius. About twenty radial spines, very stout, longer than the shell diameter, with three wing-like, prominent smooth edges. At the middle, or in the distal half, each spine bears a verticil of three strong, irregularly formed ramified branches.

Dimensions.—Diameter of the shell 0.14, pores 0.003 to 0.015, bars 0.003; length of the spines 0.16 to 0.2, breadth 0.02.

Habitat.—West Tropical Pacific, Station 220, depth 1100 fathoms.

14. Cladococcus dendrites, n. sp. (Pl. 27, fig. 5).

Pores irregular, roundish, with denticulate margin, twice to four times as broad as the bars; eight to twelve on the radius. Fifty to eighty radial spines, three-sided prismatic, with elegantly denticulated edges; in the proximal two-thirds simple, in the distal third with a bunch of ten to twenty short simple spines (three to seven on each edge).

Dimensions.—Diameter of the shell 0.16 to 0.2, pores 0.006 to 0.012, bars 0.003; length of the spines 0.2 to 0.3, breadth 0.01.

Habitat.—Antarctic Ocean, Station 157, depth 1950 fathoms.

Genus 93. Elaphococcus,^[127] Haeckel, 1881, Prodromus, p. 450.

Definition.—Astrosphærida with one simple lattice-sphere, covered with forked or dichotomously branched radial spines (the stem of the spine always forked).

The genus Elaphococcus differs from the preceding Cladococcus in the mode of ramification of the radial spines. These are forked; and the forked branches are either simple, again forked, or dichotomously ramified.

Subgenus 1. Elaphococcinus, Haeckel.

Definition.—Pores of the shell regular, of nearly equal size and similar form.

1. Elaphococcus furcatus, n. sp.

Pores of the spherical shell regular, hexagonal, four times as broad as the bars; four to five on the radius. Radial spines, arising from all the nodal-points of the network, cylindrical, as long as the radius, simply forked at the distal end; both branches half as long as the undivided part.

Dimensions.—Diameter of the shell 0.08, pores 0.01, bars 0.0025; length of the spines 0.04, breadth 0.004.

Habitat.—Tropical Atlantic, Station 348, surface.

2. Elaphococcus cervicornis, Haeckel.

Cladococcus cervicornis, Haeckel, 1862, Monogr. d. Radiol., p. 370, Taf. xiv. figs. 4-6.

Pores regular, hexagonal, ten to twenty times as broad as the bars; five to seven on the radius. Fifty to ninety radial spines (or more), arising not only from the nodal-points of the network but also from the bars between them. Each spine is cylindrical, longer than the shell diameter, and repeatedly forked (three to six times), having, therefore, numerous (thirty to sixty or more) curved branches. The distal ends of all branches fall in one spherical face.

Dimensions.—Diameter of the shell 0.07 to 0.09, pores 0.01 to 0.015, bars 0.001 to 0.015; length of the spines 0.1 to 0.15, breadth 0.005.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.

3. Elaphococcus elaphoceras, n. sp.

Pores regular, circular, hexagonally framed, three to four times as broad as the bars; six to eight on the radius. At each nodal-point of the hexagon arises a short bristle-shaped, simple by-spine. In addition, there arise from the bars thirty to sixty large main spines, longer than the shell diameter, repeatedly forked in the same way as in the preceding species.

Dimensions.—Diameter of the shell 0.1, pores 0.008, bars 0.002; length of the spines 0.12, breadth 0.002.

Habitat.—Central Pacific, Station 272. depth 2600 fathoms.

4. Elaphococcus umbellifer, n. sp.

Pores regular, circular, three times as broad as the bars; ten to twelve on the radius. Twenty to forty straight cylindrical spines, as long as the shell diameter, having at the distal end a regular umbel composed of nine to twelve curved branches of equal length, which are again ramified and resemble the inflorescence of an umbelliferous plant, the distal ends of all ramules falling in a spherical face.

Dimensions.—Diameter of the shell 0.12, pores 0.006, bars 0.002; length of the spines 0.14, breadth 0.002.

Habitat.—South Atlantic, Station 325, surface.

Subgenus 2. Elaphococculus, Haeckel.

Definition.—Pores of the shell irregular, of different size or form.

5. Elaphococcus dichotomus, n. sp.

Pores irregular, polygonal, twice to four times as broad as the bars; six to eight on the radius. Thirty to sixty radial spines cylindrical, curved, as long as the shell diameter, simply forked at the distal end; both branches one-third as long as the undivided part.

Dimensions.—Diameter of the shell 0.15, pores 0.007 to 0.015, bars 0.004; length of the spines 0.2, breadth 0.004.

Habitat.—Arctic Ocean, Greenland, surface (Koch).

6. Elaphococcus umbellatus, n. sp.

Pores irregular, roundish, or polygonal, twice to five times as broad as the bars; six to eight on the radius. Forty to sixty radial spines cylindrical, curved, as long as the shell radius, having at the distal end an irregular umbel, composed of six to twelve short branches, which are irregularly ramified or forked. (Differs from the regular Elaphococcus umbellifer mainly in the irregularity.)

Dimensions.—Diameter of the shell 0.14, pores 0.007 to 0.015, bars 0.003; length of the spines 0.12, breadth 0.01.

Habitat.—South-east Pacific (Juan Fernandez), Station 299, surface.

7. Elaphococcus drymodes, n. sp.

Pores irregular, roundish, little broader than the bars; ten to twelve on the radius. Eighty to one hundred and twenty (or more) radial spines, cylindrical, three to four times as long as the shell diameter, irregularly forked or repeatedly dichotomous (each spine with forty to sixty forked branches); the distal ends of all branches fall in a spherical plane. (Differs from the regular Elaphococcus cervicornis mainly in the irregularity.)

Dimensions.—Diameter of the shell 0.1, pores and bars 0.003 to 0.008; length of the spines 0.3 to 0.4, breadth 0.01.

Habitat.—Arctic Ocean, Iceland (Steenstrup).

Subfamily Haliommida,^[128] Haeckel.

Diplosphærida, Haeckel, 1881, Prodromus, pp. 449, 451.

Definition.—Astrosphærida with two concentric spherical lattice-shells, united by radial beams.

Genus 94. Haliomma,^[129] Ehrenberg, 1838, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 128.

Definition.—Astrosphærida with one medullary (intracapsular) and one cortical (extracapsular) shell, which are connected by radial beams, piercing the central capsule. Shell surface covered with simple radial spines of the same kind.

The genus Haliomma, one of the oldest known Radiolarian genera, contained in the catalogue of its discoverer, Ehrenberg, a large number of very different Sphærellaria, belonging to at least sixteen different genera. We limit here the conception of the genus to those Haliommida which bear simple radial spines of one kind on the surface of the cortical shell (the latter being separated from the medullary shell by the central capsule).

Subgenus 1. Haliommantha, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; spines on the whole surface (commonly one spine at each nodal-point).

1. Haliomma hexagonium, n. sp.

Cortical shell four times as broad as the medullary shell, both having very thin thread-like bars, and regular, hexagonal pores (eighteen to twenty on the radius of the outer, five to six on the radius of the inner shell). The two shells connected by twenty thin thread-like radial beams. At each nodal-point of the outer shell arises a bristle-shaped radial spine, half as long as the radius. (Similar to Heliosoma radians, Pl. 28, fig. 3, but with all the spines equal.)

Dimensions.—Diameter of the outer shell 0.2, inner 0.05; pores of the outer 0.015, of the inner 0.01; length of the spines 0.05.

Habitat.—Equatorial Atlantic, Station 347, surface.

2. Haliomma arachnium, n. sp.

Cortical shell three times as broad as the medullary shell; pores of the former regular, hexagonal, with very thin thread-like bars (fourteen to sixteen on the radius); pores of the latter regular, circular, three times as broad as the bars (four to five on the radius). The two shells connected by about forty radial beams. At each nodal-point of the outer shell arises one bristle-shaped radial spine, twice as long as the diameter of one hexagonal mesh.

Dimensions.—Diameter of the outer shell 0.15, inner 0.05; pores of the outer 0.012, of the inner 0.006; length of the spines 0.025.

Habitat.—Central Pacific, Station 266, surface.

3. Haliomma favosum, n. sp.

Cortical shell thick walled, three times as broad as the medullary shell, with regular, circular, hexagonally framed pores, twice as broad as the bars; eight to ten on the radius. Medullary shell with simple, circular pores, of the same breadth as the bars. At each nodal-point of the outer shell arises a short triangular spine three times as long as one pore.

Dimensions.—Diameter of the outer shell 0.12, inner 0.04; pores of the former 0.01, of the latter 0.005; bars 0.005; length of the spines 0.015.

Habitat.—Central Pacific, Station 271 to 274, surface.

4. Haliomma regulare, n. sp.

Cortical shell thin walled, nearly twice as broad as the medullary shell, and connected with it by forty to sixty thin radial beams. Both shells of the same perfectly regular structure, with an identical number of regular, circular pores, which are hexagonally framed, four times as broad as the bars, nine to eleven on the radius. The outer pores are twice as broad as the inner, exactly corresponding pores. Between every three pores of the outer surface (in each corner of the cortical hexagon) arises one short three-sided pyramidal spine, twice as long as the diameter of one pore.

Dimensions.—Diameter of the outer shell 0.2, of the inner 0.11; pores of the former 0.018, of the latter 0.009; length of the spines 0.04.

Habitat.—South Atlantic (Tristan da Cunha), Station 332, depth 2200 fathoms.

5. Haliomma melitomma, n. sp. (Pl. 20, fig. 4).

Melitomma formosum, Haeckel, 1879, Atlas, loc. cit.

Cortical shell thick walled, two and a half times as broad as the medullary shell, with regular pores of very elegant structure, twice as broad as the bars; eight to ten on the radius. The inner opening of each pore is simple, circular, the outer regular, six-lobed; corresponding to the six lobes are six short conical spines, which arise from the six corners of the regular hexagonal frames separating the pores. Pores of the medullary shell simple, circular, of the same breadth as the bars. The two shells connected only by six radial beams (in three dimensive axes).

Dimensions.—Diameter of the outer shell 0.17, of the inner 0.07; pores of the former 0.012, of the latter 0.004; length of the spines 0.005 to 0.01.

Habitat.—Indian Ocean, Zanzibar, Pullen, depth 2200 fathoms.

6. Haliomma lirianthus, n. sp. (Pl. 28, figs. 1, 1a, 1b).

Cortical shell thick walled, three times as broad as the medullary shell, with regular, rosette-shaped pores, twice as broad as the bars; eight to ten on the radius. The regular structure of the elegant pores is the same as in the preceding species, but without prominent crested frames (fig. 1b). Also the medullary shell (fig. 1a) is different, much thinner and smaller, with simple, circular pores, which are three times as broad as the bars. The two shells are connected by numerous (twenty?) radial beams.

Dimensions.—Diameter of the outer shell 0.15, of the inner 0.05; pores of the former 0.01, of the latter 0.005; length of the spines 0.005 to 0.02.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

7. Haliomma castanea, Haeckel.

Haliomma castanea, Haeckel, 1862, Monogr. d. Radiol., p. 428, Taf. xxiv. fig. 4.

Cortical shell thick walled, three times as broad as the medullary shell; pores of both regular, circular, twice as broad as the bars (seven to eight on the radius of the outer, four to five on the radius of the inner shell), the two connected by six to twelve (?) strong radial beams. Radial spines bristle-shaped, with conical bases, twice as long as the diameter of the cortical pores (one spine at the nodal-point between every three pores).

Dimensions.—Diameter of the outer shell 0.1 to 0.15, inner 0.03 to 0.05; pores of the former 0.005, of the latter 0.003; length of the spines 0.005 to 0.01.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.

8. Haliomma horridum, Stöhr.

Haliomma horridum, Stöhr, 1880, Palæontogr., vol. xxvi. p. 87, Taf. i. fig. 10.

Cortical shell thick walled, two and a half times as broad as the medullary shell. Pores regular, circular, of the same breadth as the bars; eight to ten on the radius. Radial spines conical, stout, nearly half as long as the radius. (Differs from the closely allied Haliomma castanea in the smaller pores and larger spines.)

Dimensions.—Diameter of the outer shell 0.14, of the inner 0.06; pores of the former 0.004, of the latter 0.02.

Habitat.—Fossil in Tertiary rocks of Barbados and Sicily; living in the Atlantic, Station 9, depth 3150 fathoms, and Station 353, depth 2965 fathoms.

9. Haliomma datura, n. sp.

Cortical shell thin walled, only one and a half times as broad as the medullary shell, both having regular, circular pores, four to six times as broad as the bars (five to six on the radius of the outer, three to four on the radius of the inner shell), the two connected by numerous (forty to sixty?) thin, short, radial beams. Radial spines conical, twice as long as the diameter of one cortical pore, arising from all the nodal-points between them.

Dimensions.—Diameter of the outer shell 0.08 to 0.12, inner 0.06 to 0.08; pores of the former 0.015 to 0.02, of the latter 0.007 to 0.012; length of the spines 0.02.

Habitat.—Central Pacific, Stations 268 to 274, surface.

Subgenus 2. Haliommetta, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; the spines not covering the entire surface, but scattered at intervals (their number smaller than that of the nodal-points of the network).

10. Haliomma circumtextum, n. sp. (Pl. 28, figs. 7, 7a).

Cortical shell very delicate, with thin thread-like bars, and regular, hexagonal pores, little larger than the thick-walled medullary shell (= 7 : 6). Pores of the latter regular, circular, double-edged, with hexagonal frames, of the same breadth as the bars; from all the hexagon-corners arise thin bristle-shaped, radial spines, twice as long as the diameter of the pores, becoming connected at equal distances from the centre by tangential threads, regularly disposed, forming the cortical shell. Twelve strong, three-sided pyramidal, radial spines, as broad at the base as one mesh, and about half as long as the radius of the shell.

Dimensions.—Diameter of the outer shell 0.14, of the inner 0.12; pores of the former 0.012, of the latter 0.005; length of the radial spines 0.04, basal breadth 0.012.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

11. Haliomma duodecinum, n. sp.

Cortical shell thick walled, three times as broad as the medullary shell. Both shells with regular, circular pores, twice as broad as the bars; eight to ten on the radius of the outer, five to six on the radius of the inner shell. Twelve conical, regularly disposed radial spines, as long as the radius, and as broad at the base as one mesh.

Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04; pores of the former 0.005, of the latter 0.002; length of the spines 0.05, basal breadth 0.005.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

12. Haliomma megaporum, Ehrenberg.

Haliomma megaporum, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 313.

Cortical shell thin walled, three times as broad as the medullary shell; the pores regular, circular, three to four on the radius, eight times as broad as the bars, quite as broad as the medullary shell, the pores of which are much smaller, twice as broad as the bars. Eight radial spines regularly disposed, conical, as long as the radius. (As the diagnosis of Ehrenberg is very incomplete, and no figure is given with it, it remains doubtful whether his Mediterranean species be identical with my Atlantic variety.)

Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04; pores of the former 0.04, of the latter 0.008; length of the spines 0.06.

Habitat.—Mediterranean (Grecian shore); North Atlantic, Station 354, surface.

13. Haliomma oculatum, Ehrenberg.

Haliomma oculatum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 74, Taf. xxviii. figs. 2, 3.

Cortical shell thick walled, four times as broad as the medullary shell; its pores regular, circular, four times as broad as the bars, six to eight on the radius. Pores of the medullary shell regular, hexagonal, with very thin bars, three to four on the radius. Nine radial spines, regularly disposed, conical, as long as the radius, as broad at the base as one cortical pore. (In the specimen figured by Ehrenberg, only two spines were preserved, seven being accidentally broken off.)

Dimensions.—Diameter of the outer shell 0.16, of the inner 0.04; pores of the former 0.01, of the latter 0.005.

Habitat.—Fossil in Barbados.

14. Haliomma enneaxiphos, n. sp.

Cortical shell thick walled, four times as broad as the dark medullary shell, with regular, circular, hexagonally framed pores, twice as broad as the bars; eight to ten on the radius. Nine radial spines regularly disposed, three sided pyramidal, as long as the radius, as broad at the base as one mesh.

Dimensions.—Diameter of the outer shell 0.11, of the inner 0.03; cortical pores 0.008, bars 0.004; length of the radial spines 0.05, basal breadth 0.012.

Habitat.—Central Pacific, Station 272, surface.

15. Haliomma tenuispinum, J. Müller.

Haliomma tenuispinum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 39, Taf. iv. fig. 9.

Haliomma tenuispinum, Haeckel, 1862, Monogr. d. Radiol., p. 431.

Cortical shell thin walled, three times as broad as the medullary shell. Both shells with very fine, thread-like bars, and regular, hexagonal pores; five to seven on the radius. Twenty radial spines, very thin, bristle-shaped, as long as the radius.

Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04; pores of the former 0.016, of the latter 0.006.

Habitat.—Mediterranean (Nice); North Atlantic, Station 353, surface.

16. Haliomma longispinum, J. Müller.

Haliomma longispinum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 39, Taf iv. fig. 8.

Haliomma longispinum, Haeckel, 1862, Monogr. d. Radiol., p. 431.

Cortical shell thick walled, three times as broad as the dark medullary shell. Pores regular, circular, hexagonally framed, twice as broad as the bars; four to six on the radius. Twenty radial spines, very long, regularly disposed, four to five times as long as the diameter of the shell, three-sided prismatic, with elegantly dentated edges, as broad as one cortical mesh.

Dimensions.—Diameter of the outer shell 0.08, of the inner 0.03; pores of the former 0.01, bars 0.005; length of the spines 0.3 to 0.4.

Habitat.—Mediterranean (Nice); Central Pacific, Station 272, surface.

17. Haliomma capense, n. sp.

Cortical shell thick walled, twice as broad as the medullary shell, both with regular, circular pores, twice as broad as the bars; eight to ten on the radius of the outer, four to six on the radius of the inner shell. Forty to sixty radial spines, conical, as long as the radius, as broad as one cortical pore.

Dimensions.—Diameter of the outer shell 0.11, of the inner 0.05; pores of the former 0.01, bars 0.005; length of the spines 0.006, basal breadth 0.012.

Habitat.—Cape of Good Hope, Station 142, surface.

18. Haliomma denticulatum, n. sp.

Cortical shell thick walled, three times as broad as the dark medullary shell, with regular, circular, double-edged pores, of the same breadth as the bars; eight to ten on the radius. Thirty to fifty radial spines, three-sided pyramidal, half as long as the radius, with three denticulated edges. (Very similar to Actinomma denticulatum, Pl. 29, fig. 3, but with simple medullary shell.)

Dimensions.—Diameter of the outer shell 0.12, inner 0.04; pores and bars of the former 0.008; length of the spines 0.04, basal breadth 0.01.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

19. Haliomma grande, n. sp.

Cortical shell thick walled, five times as broad as the dark medullary shell, with small, regular, circular pores, half as broad as the bars; twenty to twenty-four on the radius. One hundred to one hundred and twenty conical radial spines, five times as long as broad, only half as long as the radius.

Dimensions.—Diameter of the outer shell 0.4, inner 0.08; pores of the outer 0.006, bars 0.012; length of the spines 0.1, basal breadth 0.02.

Habitat.—Equatorial Atlantic, Station 348, depth 2450 fathoms.

Subgenus 3. Haliommilla, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size and form; spines covering the entire surface (commonly one spine at each nodal-point).

20. Haliomma capillaceum, Haeckel.

Haliomma capillaceum, Haeckel, 1862, Monogr. d. Radiol., p. 426, Taf. xxiii. fig. 2.

Cortical shell very thin walled, seven to eight times as broad as the medullary shell, both with irregular, polygonal pores, and very thin thread-like bars; outer pores twice to three times as broad as the inner. Radial spines very numerous, straight, bristle-shaped, about as long as the diameter of the medullary shell.

Dimensions.—Diameter of the outer shell 0.2, inner 0.025 to 0.03; outer pores 0.02 to 0.04, inner 0.008 to 0.016, bars 0.001; length of the spines 0.02 to 0.03.

Habitat.—Mediterranean (Messina), Atlantic (Canary Islands), surface.

21. Haliomma erinaceum, Haeckel.

Haliomma erinaceum, Haeckel, 1862, Monogr. d. Radiol., p. 427, Taf. xxiii. figs. 3, 4.

Cortical shell thin walled, seven to eight times as broad as the medullary shell, both with irregular, polygonal pores, two to ten times as broad as the bars, outer pores much larger than the inner. Radial spines very numerous, bristle-shaped, as long as the diameter of the medullary shell, the majority or all being either curved or obliquely depressed, the greater part neither straight nor radial.

Dimensions.—Diameter of the outer shell 0.2, inner 0.025 to 0.03; outer pores 0.005 to 0.03, inner 0.008 to 0.016, bars 0.002 to 0.004; length of the spines 0.03.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.

22. Haliomma tenellum, Haeckel.

Haliomma tenellum, Haeckel, 1862, Monogr. d. Radiol., p. 428.

Haliomma spinuloso affine, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 40, Taf. iv. fig. 7.

Cortical shell thin walled, three times as broad as the medullary shell, with irregular, roundish pores, and very thin bars. Pores of the inner shell regular, circular. Radial spines very numerous, bristle-shaped, straight, as long as the radius of the outer shell.

Dimensions.—Diameter of the outer shell 0.15, inner 0.05; outer pores 0.008 to 0.016, inner 0.005; length of the spines 0.07.

Habitat.—Mediterranean (Nice); Atlantic, Stations 349 to 354, surface.

23. Haliomma spinulosum, J. Müller.

Haliomma spinulosum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 39, Taf. iv. fig. 6.

Cortical shell thin walled, twice as broad as the medullary shell, with irregular, polygonal pores, and very thin bars. Pores of the inner shell subregular, hexagonal, ten to twelve times as broad as the bars. Radial spines very numerous, bristle-shaped, one-sixth to one-fourth as long as the radius of the outer shell.

Dimensions.—Diameter of the outer shell 0.16, inner 0.08; outer pores 0.01 to 0.03, inner 0.02; length of the spines 0.02 to 0.03.

Habitat.—Mediterranean (Nice); Central Pacific, Station 266, surface.

24. Haliomma rhodococcus, n. sp. (Pl. 19, fig. 6).

Sethosphæra rhodococcus, Haeckel, 1879, Atlas, pl. xix. fig. 6.

Cortical shell very thin walled, little larger than the thick walled medullary shell (= 10 : 9). Pores of the outer shell very irregular, roundish, twice to six times as broad as the bars, about twenty on the radius. Pores of the inner shell twice as broad as the bars, six to eight on the radius, very regular, circular on the inner, six-lobed on the outer opening, separated by prominent hexagonal crests; in the hexagon-corners arise short conical radial spines, which at equal distances from the centre are united by the outer shell, but are prominent over its surface. (A very peculiar form; the two shells may better be regarded as inner and outer cortical shell.)

Dimensions.—Diameter of the outer shell 0.2, inner 0.18; outer pores 0.04 to 0.012, inner 0.01; length of the spines 0.01.

Habitat.—Tropical Atlantic, Station 338, depth 1990 fathoms; also fossil in Barbados.

25. Haliomma boreale, n. sp.

Cortical shell thick walled, four times as broad as the medullary shell, with irregular, roundish pores, twice to four times as broad as the bars; eight to ten on the radius. Pores of the inner shell regular, circular, twice as broad as the bars, four to six on the radius. Radial spines very numerous, conical, nearly as long as the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.24, inner 0.06; outer pores 0.008 to 0.02, bars 0.005, inner pores 0.006, bars 0.003; length of the spines 0.2.

Habitat.—Arctic Ocean, Greenland ("Alert" Expedition).

Subgenus 4. Haliommura, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size and form; spines not covering the entire surface, but scattered at intervals (their number smaller than that of the nodal-points in the network).

26. Haliomma macrodoras, n. sp. (Pl. 28, figs. 6, 6a).

Cortical shell thin walled, twice as broad as the medullary shell, with irregular, polygonal meshes, three to six times as broad as the bars. Inner shell with regular, hexagonal meshes, ten times as broad as the bars. Twenty radial spines, very long, stout, three-sided prismatic, two to four times as long as the diameter of the shell, as broad as one medullary mesh, with three wing-like, denticulated edges. At the base of each spine three supporting curved beams.

Dimensions.—Diameter of the outer shell 0.14 to 0.16, of the inner 0.07 to 0.08; outer pores 0.01 to 0.02, bars 0.003; inner pores 0.01, bars 0.001; length of the spines 0.3 to 0.6, breadth 0.01.

Habitat.—Central Pacific, Station 271, surface.

27. Haliomma antarcticum, n. sp.

Cortical shell very thin walled, three times as broad as the medullary shell, with irregular, polygonal pores, and very thin thread-like bars. Inner shell with regular, hexagonal meshes, six times as broad as the bars. About forty radial spines, angular, pyramidal, half as long as the radius of the shell, as broad at the base as the largest mesh.

Dimensions.—Diameter of the outer shell 0.2, of the inner 0.07; outer pores 0.006 to 0.015, inner 0.008; length of the spines 0.05, basal breadth 0.012.

Habitat.—Antarctic Ocean, Station 154, surface.

28. Haliomma wyvillei, Haeckel.

Haliomma wyvillei, Haeckel, 1878, Protistenreich, p. 44, fig. 31.

Haliomma species, Wyville Thomson, 1877, Atlantic, vol. i. p. 236, fig. 54.

Cortical shell thin walled, three times as broad as the medullary shell. Both shells with irregular, large, polygonal pores, and very thin bars. From the inner shell arise very numerous (eighty to one hundred and twenty or more) radial spines, which pierce the outer shell, and are outside it, as long as the radius of the inner shell, straight, bristle-shaped, and as thick as the bars.

Dimensions.—Diameter of the outer shell 0.18, of the inner 0.06; pores 0.01 to 0.02, bars 0.001 to 0.002; length of the free spines 0.06.

Habitat.—Central Pacific, Stations 266 to 274, surface.

29. Haliomma beroes, Ehrenberg.

Haliomma beroes, Ehrenberg, 1854, Mikrogeol., Taf. xxxvB. B. iv. fig. 19.

Haliomma beroes, Haeckel, 1862, Monogr. d. Radiol., p. 434.

Cortical shell thin walled, three times as broad as the medullary shell, with irregular, roundish pores, twice to four times as broad as the bars. Inner shell with regular, circular pores, twice as broad as the bars. Both shells connected by four (or six ?) radial beams, perpendicularly crossed. Thirty to forty radial spines, conical, thin, shorter than the radius.

Dimensions.—Diameter of the outer shell 0.11, inner 0.04; outer pores 0.007 to 0.012, inner 0.005; length of the spines 0.03, basal breadth 0.005.

Habitat.—Atlantic, depth 2000 fathoms.

30. Haliomma compactum, n. sp. (Pl. 28, figs. 5, 5a).

Cortical shell very thick walled, four times as broad as the thin walled medullary shell; pores of the former irregular, roundish, with high polygonal frames of very different size, twice to four times as broad as the bars. Inner shell with simple, small, polygonal pores, connected with the outer shell by eight (?) regularly disposed thin radial beams, opposite in pairs, prolonged outside into strong conical spines, longer than the radius.

Dimensions.—Diameter of the outer shell 0.08, inner 0.02; outer pores 0.005 to 0.01, inner 0.005; length of the spines 0.06, basal breadth 0.012.

Habitat.—Central Pacific, Stations 265 to 272, depth 2425 to 2925 fathoms.

31. Haliomma permagnum, n. sp.

Cortical shell thick walled, six times as broad as the medullary shell, with irregular, roundish, double-edged pores, three to six times as broad as the bars. Inner shell with regular, circular pores, twice as broad as the bars. One hundred and twenty to one hundred and fifty radial spines, conical, only one-fourth as long as the radius.

Dimensions.—Diameter of the outer shell 0.42, inner 0.07; outer pores 0.012 to 0.025, bars 0.004; inner pores 0.008, bars 0.004; length of the spines 0.05, basal breadth 0.03.

Habitat.—Central Pacific, Station 268, surface.

32. Haliomma patagonicum, n. sp.

Cortical shell thick walled, four times as broad as the medullary shell, with irregular, roundish pores, twice to three times as broad as the bars. Inner shell also with irregular, roundish pores, of half the size. Forty to fifty radial spines, cylindro-conical, about as long as the shell diameter.

Dimensions.—Diameter of the outer shell 0.24, inner 0.06; outer pores 0.012 to 0.02, bars 0.006; inner pores 0.005 to 0.01, bars 0.004; length of the spines 0.3, breadth 0.02.

Habitat.—South-east Pacific, west coast of Patagonia, Station 302, surface.

33. Haliomma clavatum, n. sp.

Cortical shell thick walled, three times as broad as the medullary shell, with irregular, roundish pores little larger than the bars; eight to twelve on the radius. Inner shell with similar but smaller pores. About twenty radial spines, club-shaped, as long as the radius, three-sided, with prominent edges, twice as broad at the distal end as at the base. (Similar to Acanthosphæra clavata, Pl. 26, fig. 8, but differs from it in the possession of a medullary shell.)

Dimensions.—Diameter of the outer shell 0.2, inner 0.06; outer pores and bars 0.008 to 0.02, inner 0.006 to 0.01; length of the spines 0.1, distal breadth 0.03.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Genus 95. Heliosoma,^[130] Haeckel, 1881, Prodromus, p. 452.

Definition.—Astrosphærida with one medullary (intracapsular) and one cortical (extracapsular) shell, the two being connected by radial beams piercing the central capsule. Shell surface covered with simple radial spines of two different kinds; larger main spines and smaller by-spines.

The genus Heliosoma differs from the preceding Haliomma in the possession of two different kinds of radial spines, and exhibits therefore the same relation to it that Heliosphæra bears to Acanthosphæra among the Coscinommida. The smaller by-spines are much more numerous than the larger main spines.

Subgenus 1. Heliosomantha, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form.

1. Heliosoma radians, n. sp. (Pl. 28, figs. 3, 3a).

Cortical shell very thin walled, with thread-like bars and regular, hexagonal meshes; twenty to twenty-two on the radius. Medullary shell only one-fifth as large, of the same structure. The two shells connected by twenty very thin radial beams, which are prolonged outside into twenty stout, three-sided pyramidal main spines, as long as the diameter of the inner shell. Between these, arising from the surface, numerous bristle-shaped by-spines.

Dimensions.—Diameter of the outer shell 0.25, inner 0.05, pores 0.012; length of the main spines 0.05, basal breadth 0.012.

Habitat.—Central Pacific, Stations 266 to 274, surface.

2. Heliosoma elegans, n. sp.

Cortical shell thick walled, with regular, circular, hexagonally framed pores, twice as broad as the bars; ten to twelve on the radius. Medullary shell half as large, with simple, regular, circular pores, twice as broad as the bars. The two shells connected by twenty very thin radial beams, which are prolonged outside into twenty slender, three-sided pyramidal main spines as long as the radius. In each corner of the surface hexagons a bristle-shaped by-spine one-fourth as long.

Dimensions.—Diameter of the outer shell 0.12, inner 0.06; outer pores 0.006, bars 0.003; length of the main spines 0.05, basal breadth 0.01.

Habitat.—Central Pacific, Station 271, surface.

3. Heliosoma echinaster, Haeckel.

Haliomma echinaster, Haeckel, 1862, Monogr. d. Radiol., p. 429, Taf. xxiv. figs. 1-3.

Cortical shell thin walled, with regular, circular, hexagonally framed pores, twice as broad as the bars; ten to twelve on the radius. Medullary shell one-fourth as large, with few irregular, large, polygonal pores and very thin thread-like bars, connected with the former by nine similar thin radial beams, which are prolonged outside into nine pyramidal main spines, as long as the radius. From each corner of the surface hexagon arises a bristle-shaped by-spine, half as long as the main spine.

Dimensions.—Diameter of the outer shell 0.16, inner 0.04; outer pores 0.008, bars 0.004; length of the main spines 0.08, basal breadth 0.01.

Habitat.—Mediterranean (Messina), surface.

4. Heliosoma duodecilla, n. sp.

Cortical shell thick walled, with regular, circular pores, of the same breadth as the bars; sixteen to eighteen on the radius. Medullary shell one-third as large, of the same structure. Twelve radial main spines, regularly disposed, cylindro-conical, longer than the shell diameter, as broad as two pores. Whole surface covered with short conical by-spines.

Dimensions.—Diameter of the outer shell 0.15, inner 0.05; outer pores and bars 0.007; length of the main spines 0.2, breadth 0.02.

Habitat.—South Atlantic, Station 333, surface.

Subgenus 2. Heliosomura, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size and form.

5. Heliosoma hastatum, n. sp. (Pl. 28, fig. 4).

Cortical shell very thin walled, with large, irregular, polygonal meshes, three to six times as broad as the bars; four to six on the radius. Medullary shell one-third as large, with small, regular, circular pores. The two shells connected by twelve regularly disposed radial beams, which are prolonged outside into twelve very stout three-sided pyramidal main spines, somewhat longer than the radius, spear-shaped; each of the three wings in the middle part with one tooth. Scattered on the surface numerous by-spines of the same form, half as long and only one-fourth as broad.

Dimensions.—Diameter of the outer shell 0.1, inner 0.033; outer pores 0.006 to 0.013, inner pores 0.002, bars 0.002; length of the main spines 0.06, breadth 0.015.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

6. Heliosoma indicum, n. sp.

Cortical shell thick walled, with irregular, roundish pores, twice to five times as broad as the bars. Medullary shell of the same structure, only one-fourth as large. Thirty to forty conical main spines, as long as the radius; between them numerous bristle-shaped by-spines, only half as long.

Dimensions.—Diameter of the outer shell 0.2, inner 0.05; outer pores 0.004 to 0.01, bars 0.002; length of the main spines 0.1, breadth 0.01.

Habitat.—Indian Ocean, between Aden and Socotora, surface, Haeckel.

Genus 96. Elatomma,^[131] n. gen.

Definition.—Astrosphærida with one medullary (intracapsular) and one cortical (extracapsular) shell, the two being connected by radial beams piercing the central capsule. Shell surface covered with branched radial spines.

The genus Elatomma differs from Haliomma in the ramification of the radial spines, and exhibits therefore the same relation to it that Cladococcus, among the Coscinommida, bears to Acanthosphæra.

Subgenus 1. Elatommella, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form.

1. Elatomma pinetum, n. sp.

Cortical shell thick walled, with regular, circular, hexagonally framed pores, three times as broad as the bars. From its surface arise twenty to thirty large, three-sided prismatic, radial spines as long as the shell diameter, branched like a pine tree; on each edge of the spine five to six ramified branches, decreasing in size towards the distal end. Similar to Cladococcus pinetum (Pl. 27, figs. 1, 3), but differing in the possession of a medullary shell (one-third as large as the outer), with regular, circular pores, as broad as the bars.

Dimensions.—Diameter of the outer shell 0.2, inner 0.07; cortical pores 0.012, bars 0.004; length of the spines 0.2 to 0.24.

Habitat.—Central Pacific, Stations 266 to 272, surface.

2. Elatomma scoparium, n. sp.

Cortical shell thick walled, with regular, circular pores, twice as broad as the bars, connected with the medullary shell by twenty thin radial beams, which are prolonged outside into twenty large cylindrical radial spines somewhat longer than the radius; in the proximal half simple, in the distal half with six to nine dichotomous, irregular branches. Similar to Cladococcus scoparius (Pl. 27, fig. 2), but much larger, and with a large medullary shell (one-third as broad as the outer), and regular, circular pores.

Dimensions.—Diameter of the outer shell 0.12, inner 0.04; cortical pores 0.01, bars 0.005; length of the spines 0.08.

Habitat.—North Pacific, Station 240, surface.

Subgenus 2. Elatommura, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size or form.

3. Elatomma juniperinum, n. sp. (Pl. 28, fig. 8).

Cortical shell thin walled, with regular, polygonal, or roundish pores, twice to four times as broad as the bars, connected with the small medullary shell by about twenty thin radial beams. Inner shell only one-eighth as broad as the outer, with few irregular, polygonal meshes. Surface covered with very numerous (one hundred to one hundred and fifty or more) branched conical radial spines, one-third as long as the shell radius, with six to twelve short lateral branches.

Dimensions.—Diameter of the outer shell 0.2, inner 0.025; cortical pores 0.08 to 0.016, bars 0.004; length of the spines 0.04.

Habitat.—Central Pacific, Station 271, surface.

4. Elatomma penicillus, n. sp.

Cortical shell thin walled, with irregular, polygonal pores, twice to four times as broad as the bars, connected with the medullary shell by twenty (or more?) very thin beams. These are prolonged outside into twenty straight, three-sided prismatic, radial spines as long as the radius, with a brush-like bunch of six to nine short, irregularly ramified branches at the end. Medullary shell very delicate (half as broad as the outer), with regular, hexagonal meshes and thread-like bars.

Dimensions.—Diameter of the outer shell 0.15, inner 0.08; length of the spines 0.08.

Habitat.—West coast of Norway, Bergen, Haeckel.

5. Elatomma irregulare, n. sp.

Cortical shell thin walled, with irregular, polygonal, or roundish meshes, twice to six times as broad as the bars; the medullary shell of the same structure, half as broad, with smaller irregular pores. Forty to sixty curved, three-sided, radial spines, as long as the shell, with a bunch of very irregular, curved, and partly ramified branches at the distal end.

Dimensions.—Diameter of the outer shell 0.2, inner 0.1; length of the spines 0.2, breadth 0.01.

Habitat.—North Atlantic, Gulf Stream, Færöe Channel, surface, John Murray.

Genus 97. Leptosphæra,^[132] n. gen.

Definition.—Astrosphærida with two extracapsular cortical shells without by-spines, connected by long prismatic radial spines.

The genus Leptosphæra, together with the three following genera, forms the very peculiar and typical small group of Sphæroidea which we call the Diplosphærida (with four genera and twenty-four species); their shell is composed of two concentric spheres as in the three foregoing genera; but whilst in these the inner shell is an intracapsular medullary shell and the outer an extracapsular cortical shell, in the Diplosphærida both shells are extracapsular or cortical shells, therefore the inner shell of the latter corresponds to the outer of the former. The inner spherical shell of all Diplosphærida is composed of very delicate beams and large pores, which are either regular hexagonal or irregular polygonal (never roundish). From its surface arise a variable number (twenty to thirty) of stout long radial spines, which are invariably longer than the shell diameter (often two to three times as long or more), and of three-sided prismatic form, the three edges either smooth or serrate, often with three rows of lateral branches (commonly three to five branches in each row); the latter are invariably of the same form, concavely curved towards the spine, and decrease in size towards the distal end. From the three edges of each main spine in all Diplosphærida, at equal distances from the centre, arise six very thin, thread-like lateral branches (a pair from each edge) and connect the spine in a tangential direction with all neighbouring spines. In this manner the polyhedral outer shell is formed, the meshes of which therefore are always very large and triangular. Sometimes each of these primary triangular meshes becomes filled up with a secondary network, either of regular quadrangular or of irregular polygonal secondary meshes. Besides the constant twenty to thirty large main spines, in the majority of Diplosphærida bristle-shaped radial by-spines arise, either from the inner shell (Diplosphæra) or from the outer (Drymosphæra), or from both (Astrosphæra). They are absent only in Leptosphæra. Commonly the by-spines are simple, rarely forked or branched. The central capsule in the Diplosphærida is usually enclosed in the inner shell; often it completely fills up the latter, or drives out a cæcal protuberance through each mesh; but these processes rarely unite outside. The average size of the Diplosphærida, which are all pelagic organisms, is much larger than that of the other Haliommida.

Subgenus 1. Leptosphærella, Haeckel.

Definition.—Radial spines simple, without lateral branches.

1. Leptosphæra hexagonalis, n. sp. (Pl. 19, fig. 2).

Inner shell with regular, hexagonal meshes, and very thin, thread-like bars; outer shell twice as broad, with simple triangular meshes. Radial spines with three smooth edges. (Fig. 2 represents the central capsule with numerous club-shaped saccules, prominent externally through the meshes; in the centre a large simple spherical nucleus, one-third as broad as the capsule. The skeleton of this species is identical with that of Diplosphæra hexagonalis, Pl. 19, fig. 3, but has no by-spines.)

Dimensions.—Diameter of the outer shell 0.3, of the inner 0.15.

Habitat.—Cosmopolitan; Mediterranean (Corfu), North Atlantic (Canary Islands), Tropical Pacific, surface.

2. Leptosphæra serrata, n. sp.

Inner shell with regular, hexagonal meshes, five to six times as broad as the bars; outer shell three times as broad, with simple triangular meshes. Radial spines with three serrated edges (of the same form as the main spines of Drymosphæra dendrophora, Pl. 20, fig. 1).

Dimensions.—Diameter of the outer shell 0.45, of the inner 0.15.

Habitat.—Central Pacific, Station 271, surface.

3. Leptosphæra polygonalis, n. sp.

Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell twice as broad, with simple triangular meshes. Radial spines with three smooth edges. (Resembles Drymosphæra polygonalis, Pl. 19, fig. 1, but has no by-spines.)

Dimensions.—Diameter of the outer shell 0.35, inner 0.175.

Habitat.—North Pacific, Station 256, surface.

Subgenus 2. Leptosphæromma, Haeckel.

Definition.—Radial spines with three rows of lateral branches (one row on each edge).

4. Leptosphæra ciliata, n. sp.

Inner shell with regular, hexagonal meshes and very thin thread-like bars; outer shell three times as broad, with simple triangular meshes. Radial spines with smooth edges and three rows of simple, smooth, curved, lateral branches (six branches on each edge), similar to those of Diplosphæra gracilis.

Dimensions.—Diameter of the outer shell 0.6, inner 0.2.

Habitat.—South Atlantic, Station 325, surface.

5. Leptosphæra spinosa, Haeckel.

Diplosphæra spinosa, R. Hertwig, 1879, Organismus d. Radiol., p. 40, Taf. v. fig. 2.

Inner shell with regular, hexagonal meshes, five times as broad as the bars; outer shell three times as broad, with simple triangular meshes. Radial spines with three densely serrated edges, and with three rows of serrated, simple, curved, lateral branches (three branches on each edge). Differs from the preceding in the thicker bars and the elegantly denticulated spines and branches.

Dimensions.—Diameter of the outer shell 0.66, inner 0.22.

Habitat.—Mediterranean (Messina), R. Hertwig.

6. Leptosphæra stellata, n. sp.

Inner shell with regular, hexagonal meshes, six times as broad as the bars, each bar crossed by a transverse tangential rod, so that each mesh represents an elegant six-rayed star (as in Astrosphæra stellata, Pl. 19, fig. 5, but without radial by-spines); outer shell twice as broad, with simple triangular meshes. Radial spines with serrated edges and three rows of simple lateral branches (four branches on each edge).

Dimensions.—Diameter of the outer shell 0.44, inner 0.22.

Habitat.—Tropical Atlantic (Ascension Island), Station 343, surface.

7. Leptosphæra reticulum, n. sp.

Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell four times as broad, also with irregular, polygonal meshes, the sides of the triangular main meshes being connected by irregular lateral ramules, forming an extremely delicate reticulum.

Dimensions.—Diameter of the outer shell 0.64, inner 0.16.

Habitat.—South Pacific, Station 291, surface.

Genus 98. Diplosphæra,^[133] Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 804.

Definition.—Astrosphærida with two extracapsular cortical shells, connected by long, prismatic, radial spines; inner shell with thin radial by-spines.

The genus Diplosphæra differs from its ancestral form Leptosphæra in the development of radial by-spines on the surface of the inner shell, the outer shell being smooth.

Subgenus 1. Diplosphærella, Haeckel.

Definition.—Radial main spines simple, without lateral branches.

1. Diplosphæra hexagonalis, n. sp. (Pl. 19, fig. 3).

Inner shell with regular, hexagonal meshes and very thin thread-like bars; at each nodal-point one bristle-shaped by-spine; outer shell twice as broad, with simple triangular meshes. Radial spines with three smooth edges. (The radially striped central capsule, enclosed in the inner shell, envelops a large central nucleus one-third its size, fig. 3.)

Dimensions.—Diameter of the outer shell 0.36, inner 0.18.

Habitat.—Central Pacific, Stations 265 to 274, surface.

2. Diplosphæra ornata, n. sp.

Inner shell with regular, hexagonal meshes, four times as broad as the bars; outer shell three times as broad, with simple triangular meshes. Radial main spines as well as the bars of both shells very elegantly denticulated; radial by-spines (very numerous in the surface of the inner shell) smooth.

Dimensions.—Diameter of the outer shell 0.7, inner 0.24.

Habitat.—Indian Ocean, Madagascar, surface, Rabbe.

3. Diplosphæra dictyota, n. sp.

Inner shell with regular, hexagonal meshes, six times as broad as the bars; at each nodal-point one radial by-spine; outer shell two and a half times as broad, with very delicate square meshes, separated by thread-like bars which arise from the sides of the triangular main meshes. Radial main spines with three serrated edges. (Differs from the similar Diplosphæra gracilis in the simple main spines, with delicate dentition of the edges.)

Dimensions.—Diameter of the outer shell 0.5, inner 0.2.

Habitat.—North Atlantic, Canary Islands, surface.

4. Diplosphæra polygonalis, n. sp.

Inner shell with irregular, polygonal meshes and very thin thread-like bars, covered with very numerous bristle-shaped by-spines; outer shell twice as broad, with simple triangular meshes. Radial main spines with three smooth edges.

Dimensions.—Diameter of the outer shell 0.44, inner 0.22.

Habitat.—South Pacific, Station 288, surface.

Subgenus 2. Diplosphæromma, Haeckel.

Definition.—Radial main spines with three rows of lateral branches (one row on each edge).

5. Diplosphæra gracilis, Haeckel.

Diplosphæra gracilis, Haeckel, 1862, Monogr. d. Radiol., p. 354, Taf. x. fig. 1.

Inner shell with regular, hexagonal meshes and very thin bars; at each nodal-point one simple bristle-shaped radial by-spine; outer shell twice as broad, with very delicate square meshes, separated by thread-like bars which arise from the sides of the triangular main meshes. Radial spines with smooth edges and with three rows of simple curved lateral branches (four to six branches on each edge).

Dimensions.—Diameter of the outer shell 0.54, inner 0.27.

Habitat.—Mediterranean (Messina).

6. Diplosphæra denticulata, n. sp.

Inner shell with regular, hexagonal meshes, four times as broad as the bars; at each nodal-point is a simple bristle-shaped by-spine; outer shell three times as broad, with simple triangular meshes. Radial spines very strong, with dentated edges and with three rows of lateral branches (six dentated curved branches on each edge).

Dimensions.—Diameter of the outer shell 0.4, inner 0.13.

Habitat.—North Atlantic, Azores, surface.

7. Diplosphæra reticulata, n. sp.

Inner shell with regular, hexagonal meshes, five times as broad as the bars, which are densely covered with very numerous, simple bristle-shaped by-spines; outer shell four times as broad, with very numerous small irregular polygonal meshes, forming a very delicate network, and filling out the large triangular main meshes. Radial spines with three serrated edges and three rows of short curved branches (four to five branches on each edge).

Dimensions.—Diameter of the outer shell 0.6, inner 0.15.

Habitat.—North Atlantic, Gulf Stream, Færöe Channel, surface, John Murray.

8. Diplosphæra triglochin, n. sp.

Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell three times as broad, with similar irregular polygonal meshes, filling out the large triangular main meshes. Radial spines with three serrated edges, each of which bears one single large lateral branch, concavely curved towards the distal end. By-spines of the inner shell very numerous.

Dimensions.—Diameter of the outer shell 0.5, inner 0.17.

Habitat.—Central Pacific, Station 264, surface.

Genus 99. Drymosphæra,^[134] Haeckel, 1881, Prodromus, p. 452.

Definition.—Astrosphærida with two extracapsular cortical shells, connected by long prismatic, radial spines; outer shell with thin radial by-spines.

The genus Drymosphæra differs from its ancestral form Leptosphæra in the development of radial by-spines on the surface of the outer shell, the inner shell being smooth.

Subgenus 1. Drymosphærella, Haeckel.

Definition.—Radial by-spines simple, not branched (main spines simple).

1. Drymosphæra hexagonalis, n. sp.

Inner shell with regular, hexagonal meshes and very thin thread-like bars; outer shell twice as broad, with simple triangular meshes and thin thread-like bars, which bear very numerous, bristle-shaped radial by-spines. Radial main spines with three smooth edges. (Differs from the first species of the other three genera of Diplosphærida in the presence of by-spines on the outer, and their absence on the inner shell.)

Dimensions.—Diameter of the outer shell 0.32, inner 0.16.

Habitat.—Central Pacific, Station 274, surface.

2. Drymosphæra polygonalis, n. sp. (Pl. 19, fig. 1).

Diplosphæra polygonalis, Haeckel, 1879, Atlas.

Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell one and a half times as broad, with simple triangular meshes and thicker bars, which bear numerous bristle-shaped radial by-spines (in the figure the majority of these are broken off). Radial main spines with three smooth edges. (Similar to Leptosphæra polygonalis and Diplosphæra polygonalis, but differs from both in the presence of by-spines on the outer, and their absence on the inner shell.)

Dimensions.—Diameter of the outer shell 0.33, inner 0.22.

Habitat.—North Pacific, Station 236 south of Japan, surface.

Subgenus 2. Drymosphæromma, Haeckel.

Definition.—Radial by-spines forked or branched (main spines simple).

3. Drymosphæra furcata, n. sp.

Inner shell with irregular, polygonal meshes and thin bars, the former five times as broad as the latter; outer shell two and a half times as broad, with simple triangular meshes and smooth bars, bearing numerous long smooth bristle-shaped by-spines, which in the distal half are forked. Radial main spines with three smooth edges.

Dimensions.—Diameter of the outer shell 0.4, inner 0.16.

Habitat.—Indian Ocean, Ceylon, surface, Haeckel.

4. Drymosphæra cladophora, n. sp.

Inner shell with irregular, polygonal meshes, three to six times as broad as the smooth bars; outer shell twice as broad, with simple triangular meshes and very thin smooth bars, bearing numerous curved, irregularly branched, smooth by-spines. Radial main spines with three serrated edges.

Dimensions.—Diameter of the outer shell 0.4, inner 0.2.

Habitat.—Central Pacific, Station 276, surface.

5. Drymosphæra dendrophora, n. sp. (Pl. 20, figs. 1, 1a, 1b).

Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell one and a half times as broad, with simple triangular meshes and thicker bars, which bear a forest of very numerous, repeatedly dichotomous or irregularly branched, curved by-spines, longer than the diameter of the outer shell. Radial main spines with three dentated edges. All parts of the skeleton, the net bars as well as the radial beams and spines, are very elegantly denticulated (fig. 1b). The central capsule (fig. 1a) completely distends the inner shell and forces out protuberances through all its pores; in its centre lies a nucleus one-third its size.

Dimensions.—Diameter of the outer shell 0.25, inner 0.16.

Habitat.—Central Pacific, Station 271, surface.

Genus 100. Astrosphæra,^[135] n. gen.

Definition.—Astrosphærida with two extracapsular cortical shells, connected by long, prismatic, radial spines; inner and outer shell with thin radial by-spines.

The genus Astrosphæra differs from its ancestral form, Leptosphæra, in the development of radial by-spines on the surface of both shells.

Subgenus 1. Astrosphærella, Haeckel.

Definition.—Radial main spines simple without lateral branches.

1. Astrosphæra hexagonalis, n. sp. (Pl. 19, fig. 4).

Inner shell with regular, hexagonal meshes and very thin bars, having a bristle-shaped, short radial by-spine in each hexagon-corner; outer shell twice as broad, with simple triangular meshes and thicker bars, bearing one row of simple bristle-shaped, curved, radial by-spines. Radial main spines with three smooth edges.

Dimensions.—Diameter of the outer shell 0.32, inner 0.16.

Habitat.—South Pacific (West Patagonia), Station 302, surface.

2. Astrosphæra splendens, n. sp.

Inner shell with regular, hexagonal meshes, four times as broad as the bars, and covered with numerous curved, long, bristle-shaped by-spines; outer shell three times as broad, with simple triangular meshes and thin bars, bearing a row of very long, curved, bristle-shaped by-spines. Radial main spines with three dentated edges. All parts of the skeleton elegantly denticulated, as in Drymosphæra dendrophora (Pl. 20, fig. 1).

Dimensions.—Diameter of outer shell 0.7, inner 0.24.

Habitat.—Tropical Atlantic, Station 347, surface.

Subgenus 2. Astrosphæromma.

Definition.—Radial main spines with three rows of lateral branches (one row on each edge).

3. Astrosphæra sideræa, n. sp.

Inner shell with regular, hexagonal meshes, six times as broad as the bars, and covered with numerous short bristle-shaped by-spines; outer shell four times as broad, with simple triangular meshes, and rows of long bristle-shaped by-spines arising from the bars. Radial main spines with three serrated edges and three rows of lateral branches (four branches on each edge).

Dimensions.—Diameter of the outer shell 0.6, inner 0.15.

Habitat.—Central Pacific, Station 266, surface.

4. Astrosphæra stellata, n. sp. (Pl. 19, fig. 5).

Diplosphæra stellata, Haeckel, 1881, Prodrom. et Atlas.

Inner shell with regular, hexagonal, six-rayed meshes, each bar being crossed by a transverse tangential rod, at each nodal-point a long bristle-shaped by-spine; outer shell three times as broad, with simple triangular meshes and denticulated thin bars, bearing a row of bristle-shaped radial by-spines. Radial main spines in the proximal half with three serrated edges, in the distal half with three rows of curved lateral branches (five branches on each edge).

Dimensions.—Diameter of the outer shell 0.6, inner 0.2.

Habitat.—Central Pacific, Station 274, surface.

Subfamily Actinommida,^[136] Haeckel, 1862, Monogr. d. Radiol., p. 440 (sensu emendato).

Definition.—Astrosphærida with three concentric, spherical, lattice-shells, united by radial beams.

Genus 101. Actinomma,^[137] Haeckel, 1862, Monogr. d. Radiol., p. 440.

Definition.—Astrosphærida with three concentric lattice-spheres and numerous simple radial spines of one kind.

The genus Actinomma is here restricted to those Sphæroidea which combine the possession of three concentric lattice-shells with numerous radial spines on the surface; the spines are all simple, being of one and the same kind. Commonly two of the three shells are intracapsular medullary shells, connected by radial beams (piercing the central capsule) with the outer, extracapsular, cortical shell. But in some species only one medullary shell is enclosed in the central capsule, whilst both other shells lie outside it. In such case the distance between these two cortical shells is much smaller than their distance from the simple internal medullary shell. These forms correspond more to aculeate Rhodosphæræ, whilst the others resemble aculeate Thecosphæræ.

Subgenus 1. Actinommantha, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; spines on the entire surface (commonly one spine at each nodal-point).

1. Actinomma hexagonium, n. sp.

Cortical shell, as well as both medullary shells, very thin walled, with regular, hexagonal pores and thread-like bars between them. Pores of the outer shell twice as broad as those of the middle, and three times as broad as those of the inner shells. Radial proportion of the three spheres = 1 : 3 : 9; about twenty thin radial beams between them. At each nodal-point of the surface arises one bristle-shaped radial spine, half as long as the radius.

Dimensions.—Diameter of the outer shell 0.22, middle 0.07, inner 0.025; meshes of the cortical shell 0.01; length of the spines 0.05.

Habitat.—Central Pacific, Stations 270 to 274, surface.

2. Actinomma facetum, n. sp.

Cortical shell thick walled, with regular, circular, hexagonally framed pores, three times as broad as the bars. Pores of both medullary shells regular, circular. Radial proportion of the three spheres = 1 : 2 : 4; about forty thin radial beams between them. At each nodal-point of the surface arises one short, three-sided pyramidal, radial spine, about one-third as long as the radius.

Dimensions.—Diameter of the outer shell 0.16, middle 0.08, inner 0.04; cortical pores 0.012, bars 0.004; length of the spines 0.03, basal breadth 0.015.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

3. Actinomma anthomma, n. sp.

Cortical shell thick walled, with regular, six-lobed pores, twice as broad as the bars. At each nodal-point of the surface is one short conical radial spine, as long as the diameter of the pores; one corresponding to each lobe, and there is therefore around each pore a regular corona of six spines, as in Haliomma lirianthus (Pl. 28, fig. 1b). Both medullary shells with simple, circular, regular pores. Radial proportion of the three spheres = 1 : 2.5 : 7; radial beams between them only six, opposite in pairs in the three dimensive axes.

Dimensions.—Diameter of the outer shell 0.2, middle 0.075, inner 0.003; cortical pores 0.01, bars 0.005; length of the spines 0.01.

Habitat.—Central Pacific, Station 271, surface.

4. Actinomma castanomma, n. sp.

Cortical shell as well as both medullary shells thick walled, with regular, circular pores, twice as broad as the bars; between them at each nodal-point one bristle-shaped radial spine, one-third as long as the radius, with conical base. Radial proportion of the three spheres = 2 : 3 : 8; only six radial beams between them (opposed in pairs in the three dimensive axes).

Dimensions.—Diameter of the outer shell 0.15, middle 0.06, inner 0.04; cortical pores 0.008, bars 0.004; length of the spines 0.025.

Habitat.—South Atlantic, Station 333, surface.

5. Actinomma entactinia, Stöhr.

Actinomma entactinia, Stöhr, 1880, Palæontogr., vol. xxvi. p. 93, Taf. ii. fig. 12.

Cortical shell as well as both medullary shells thick walled, with regular, circular pores, of the same breadth as the bars. Radial proportion of the three spheres = 1 : 3 : 8; radial beams between them very numerous (thirty to fifty or more?). Entire surface covered with short thick conical spines, only one-fifth as long as the radius.

Dimensions.—Diameter of the outer shell 0.16, middle 0.06, inner 0.02; cortical pores and bars 0.007; length of the spines 0.015.

Habitat.—Fossil in the Tertiary rocks of Sicily, Grotte, Caltanisetta.

Subgenus 2. Actinommetta, Haeckel.

Definition.—Pores of the outer shell regular, of nearly equal size and similar form; spines not over the entire surface, but scattered at intervals (their number smaller than that of the nodal-points).

6. Actinomma japonicum, n. sp.

Cortical shell thick walled, with regular, circular, hexagonally framed pores, three times as broad as the bars. Both medullary shells with simple, circular, regular pores, of the same breadth as the bars. Radial proportion of the three spheres = 2 : 5 : 9; radial beams between them twenty, prolonged outside into twenty symmetrically disposed, three-sided pyramidal spines, as long as the radius.

Dimensions.—Diameter of the outer shell 0.18, middle 0.1, inner 0.04; cortical pores 0.01, bars 0.003; length of the spines 0.1, basal breadth 0.012.

Habitat.—North Pacific, Station 240, east of Japan, surface.

7. Actinomma denticulatum, n. sp. (Pl. 29, fig. 3).

Cortical shell thick walled, with regular, circular, double-edged pores, twice as broad as the bars. Forty to fifty radial spines, three-sided pyramidal, half as long as the radius, with three elegantly denticulated edges. Radial proportion of the three spheres = 1 : 2 : 5. (Differs from Haliomma denticulatum only in the double medullary shell and larger size.)

Dimensions.—Diameter of the outer shell 0.14, middle 0.06, inner 0.03; cortical pores 0.01, bars 0.005; length of the spines 0.04, basal breadth 0.01.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

8. Actinomma trinacrium, Haeckel.

Actinomma trinacrium, Haeckel, 1862, Monogr. d. Radiol., p. 441, Taf. xxiv. figs. 6-8.

Haliomma trinacrium, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 815.

Cortical shell as well as both medullary shells thin walled, with subregular, circular pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 3 : 9; radial beams between them twenty, prolonged outside into strong, three-sided pyramidal spines, as long as the radius; between them, on the surface, numerous similar spines. Sometimes the latter remain smaller, the pores more irregular, and then this species corresponds to Echinomma trinacrium.

Dimensions.—Diameter of the outer shell 0.09, middle 0.03, inner 0.01; cortical pores 0.008, bars 0.004; length of the spines 0.04, basal breadth 0.01.

Habitat.—Mediterranean (Messina, Corfu, Haeckel), surface.

9. Actinomma pachyderma, n. sp. (Pl. 29, figs. 4, 5).

Cortical shell very thick walled, with regular, circular, double-edged pores, twice as broad as the bars. Both medullary shells with simple, small, circular pores, of the same breadth as the bars. Radial proportion of the three spheres = 1 : 2 : 4; radial spines about twenty, conical, shorter than the radius, prolonged inside into twenty very thin connecting beams (fig. 4).

Dimensions.—Diameter of the outer shell 0.08, middle 0.04, inner 0.02; cortical pores 0.01; bars 0.005; length of the spines 0.03, basal breadth 0.01.

Habitat.—South Pacific, Station 297, depth 1775 fathoms.

Subgenus 3. Actinommilla, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size and form; spines over the entire surface (commonly one spine at each nodal-point).

10. Actinomma spinigerum, Stöhr.

Actinomma spinigerum, Stöhr, 1880, Palæontogr., vol. xxvi. p. 92, Taf. ii. fig. 10.

Cortical shell thick walled, with irregular, roundish, or subcircular pores, twice to four times as broad as the bars. Radial proportion of the three spheres = 1 : 3 : 8; between them eight (?) connecting radial beams. Entire surface densely covered with small conical spines, not larger than the pores.

Dimensions.—Diameter of the outer shell 0.17, middle 0.07, inner 0.023; cortical pores 0.006 to 0.012, bars 0.003; length of the spines 0.01.

Habitat.—Fossil in Tertiary rocks of Sicily, Grotte, Stöhr.

11. Actinomma hirsutum, n. sp.

Cortical shell thick walled, with irregular, roundish pores, about the same breadth as the bars. Radial proportion of the three spheres = 1 : 2 : 8; between them numerous (twenty to thirty or more) cylindrical connecting beams. Entire surface densely covered with innumerable small bristle-shaped spines, as long as the diameter of the inner shell.

Dimensions.—Diameter of the outer shell 0.25, middle 0.06, inner 0.03; cortical pores and bars 0.004 to 0.008; length of the spines 0.03.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Subgenus 4. Actinommura, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size and form; spines not over the entire surface, but scattered at intervals (their number smaller than that of the nodal-points).

12. Actinomma capillaceum, n. sp. (Pl. 29, fig. 6).

Cortical shell very thin walled, with irregular, polygonal meshes (sixteen to eighteen on the radius), three to six times as broad as the bars. Both medullary shells with smaller pores of the same structure. Radial proportion of the three spheres = 1 : 2.5 : 7; radial connecting beams between them very thin and numerous (one hundred and twenty to one hundred and fifty or more), each prolonged outside into a short three-sided pyramidal spine, as long as the radius of the inner shell. (Similar to Haliomma capillaceum.)

Dimensions.—Diameter of the outer shell 0.27, middle 0.1, inner 0.04; cortical pores 0.01 to 0.02, bars 0.003; length of the spines 0.02, basal breadth 0.005.

Habitat.—Central Pacific, Stations 266 to 274, surface.

13. Actinomma arcadophorum, n. sp. (Pl. 29, figs. 7, 8).

Cortical shell very thin walled, with irregular, polygonal meshes, ten to twenty times as broad as the bars; twelve to sixteen on the radius. Both medullary shells with similar delicate network. Radial proportion of the three spheres = 1 : 2 : 6; numerous thin radial beams (forty to eighty or more) connect both medullary shells and alternate with other beams, which arise from arcade-shaped protuberances of the outer medullary shell, and connect it with the cortical shell. Outer prolongations of these form the bristle-shaped spines of the surface.

Dimensions.—Diameter of the outer shell 0.22, middle 0.09, inner 0.04; cortical pores 0.01 to 0.02, bars 0.001 to 0.002; length of the radial spines 0.2.

Habitat.—Central Pacific, Station 266, surface.

14. Actinomma schwageri, Stöhr.

Actinomma schwageri, Stöhr, 1880, Palæontogr., vol. xxvi. p. 92, Taf. ii. fig. 9a, b.

Cortical shell thick walled, with irregular, large, polygonal meshes, five to twelve times as broad as the bars; six to eight on the radius. Both medullary shells with very small, circular, regular pores. Radial proportion of the three spheres = 1 : 2 : 9; connecting radial beams between them nine, prolonged outside into nine short stout, three-sided pyramidal spines, as long as the diameter of the inner shell.

Dimensions.—Diameter of the outer shell 0.17, middle 0.04, inner 0.02; cortical pores 0.01 to 0.03, bars 0.006 and less; length of the spines 0.02, basal breadth 0.01.

Habitat.—Fossil in Tertiary rocks of Sicily, Grotte, Stöhr.

15. Actinomma dodecomma, n. sp.

Cortical shell thin walled, with irregular, roundish pores, three to six times as broad as the bars. Both medullary shells with regular, circular pores, twice as broad as the bars. Radial proportion of the three shells = 1 : 2.5 : 7; connecting radial beams between them twelve, regularly disposed, prolonged outside into twelve strong, three-sided pyramidal spines, as long as the radius.

Dimensions.—Diameter of the outer shell 0.14, middle 0.05, inner 0.02; cortical pores 0.008 to 0.018, bars 0.003; length of the spines 0.08, breadth 0.02.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

16. Actinomma pachycapsa, n. sp.

Cortical shell very thick walled, with irregular, roundish pores, twice to four times as broad as the bars; twelve to sixteen on the radius. Radial proportion of the three spheres = 1 : 3 : 12. Both medullary shells of similar irregular structure, connected with the cortical shell by twelve regularly disposed radial beams, which are prolonged outside into twelve short stout conical spines, as long as the diameter of the middle shell.

Dimensions.—Diameter of the outer shell 0.25, middle 0.06, inner 0.02; cortical pores 0.006 to 0.012, bars 0.003; length of the spines 0.05, breadth 0.02.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

17. Actinomma giganteum, n. sp.

Cortical shell thick walled, little larger than the outer medullary shell, whilst the inner is only one-tenth as large. Pores of all three shells irregular, roundish, or subcircular, twice to three times as broad as the bars, on an average twice as large in the outer and middle as in the inner shell. Sixty to eighty short conical radial spines on the surface, about as long as the diameter of the inner shell, and one-fourth as broad at the base. Radial proportion of the three spheres = 1 : 9 : 10.

Dimensions.—Diameter of the outer shell 0.4 to 0.5, middle 0.35 to 0.45, inner 0.05 to 0.06.

Habitat.—Fossil in Barbados.

Genus 102. Echinomma,^[138] Haeckel, 1881, Prodromus, p. 453.

Definition.—Astrosphærida with three concentric lattice-spheres and numerous simple radial spines of two different kinds; larger main spines and smaller by-spines.

The genus Echinomma, differs from its ancestral form, Actinomma, in the differentiation of the radial spines. Whilst a large number of small by-spines cover the entire surface, a smaller number of large main spines are scattered over it, or limited to certain regularly distributed points. It represents Heliosoma among the Haliommida.

Subgenus 1. Echinommetta, Haeckel.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form.

1. Echinomma echinidium, n. sp.

Cortical shell thin walled, with regular, hexagonal pores, four times as broad as the bars; ten to twelve on the radius. Both medullary shells with regular, circular pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 5. Surface covered with short bristle-shaped by-spines (one in every hexagon-corner); twenty main spines regularly disposed, three-sided pyramidal, as long as the diameter of the inner shell.

Dimensions.—Diameter of the outer shell 0.1, middle 0.045, inner 0.02; cortical pores 0.008, bars 0.002; length of the main spines 0.02, breadth 0.01.

Habitat.—South Pacific, Station 295, surface.

2. Echinomma cidaris, n. sp.

Cortical shell thin walled, with regular, circular, hexagonally framed pores, twice as broad as the bars; six to eight on the radius. Both medullary shells with simple, circular pores. Radial proportion of the three spheres = 1 : 2 : 6. Surface covered with short bristle-shaped by-spines, half as long as the forty to fifty main spines, which are three-sided pyramidal, and reach the radius of the shell.

Dimensions.—Diameter of the outer shell 0.18, middle 0.06, inner 0.03; cortical pores 0.01, bars 0.005; length of the main spines 0.08, basal breadth 0.015.

Habitat.—Central Pacific, Station 272, surface.

3. Echinomma aculeatum, Haeckel.

Actinomma aculeatum, Stöhr, 1880 Palæontogr., vol. xxvi. p. 92, Taf. ii. fig. 11.

Cortical shell thick walled with regular circular pores, of the same breadth as the bars; eight to ten on the radius. Radial proportion of the three spheres = 1 : 2 : 8. Surface covered with short conical by-spines about twenty strong main spines, three-sided pyramidal, one-third as long as the shell diameter.

Dimensions.—Diameter of the outer shell 0.16, middle 0.04, inner 0.02; cortical pores and bars 0.003; length of the main spines 0.05, basal breadth 0.013.

Habitat.—Fossil in the Tertiary rocks of Sicily and Barbados; living in the Atlantic, Station 332, depth 2200 fathoms.

4. Echinomma diadema, n. sp.

Cortical shell thick walled with regular circular pores, twice as broad as the bars; sixteen to eighteen on the radius. Radial proportion of the three spheres = 1 : 3 : 11. Surface covered with short bristle-shaped by-spines one third as long as the twelve stout conical main spines, which reach in length the radius, and lie opposite in pairs in six axes.

Dimensions.—Diameter of the outer shell 0.22, middle 0.06, inner 0.02; cortical pores 0.006, bars 0.003 length of the main spines 0.12, basal breadth 0.02.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

Subgenus 2. Echinommura, Haeckel.

Definition.—Pores of the cortical shell irregular, of different size or form.

5. Echinomma sphærechinus, n. sp. (Pl. 29, fig. 2).

Actinomma sphærechinus, Haeckel, 1879, Atlas (pl. xxix. fig. 2).

Cortical shell thin walled, with irregular, roundish pores, twice to five times as broad as the bars; five to seven on the radius. Both medullary shells with regular, circular pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 4. Surface covered with thirty to fifty pyramidal main spines, as long as the diameter of the inner shell, and with numerous small conical by-spines of half the length.

Dimensions.—Diameter of the outer shell 0.11, middle 0.05, inner 0.025; cortical pores 0.01 to 0.02, bars 0.004; length of the main spines 0.03, basal breadth 0.005.