Chapter XI: Literature and History (5)

Both shells with the same number of pores, exactly corresponding, about ten on the quadrant. {77}All pores regular, or subregular, hexagonal; the outer twice as broad as the inner. Outer bars very thin, thread-like; inner bars thick, one-third as broad as the pores. Surface smooth. Both shells connected by numerous radial beams, their distance one-third as large as the radius of the inner shell.

_Dimensions._--Diameter of the outer shell 0.16, inner 0.12, distance of both 0.02; outer pores 0.014, inner pores 0.007.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

2. _Liosphæra rhodococcus_, n. sp.

Both shells with the same number of pores, exactly corresponding, about twelve on the quadrant. All pores regular or subregular; the inner circular, with elegant six-lobed frames, twice as broad as the bars; the outer hexagonal, with very thin thread-like bars. All corners of the outer and inner hexagons connected by thin, bristle-shaped radial beams. (Similar to _Haliomma rhodococcus_, Pl. 19, fig. 6; but with smooth surface and regular hexagonal pores of the outer shell.)

_Dimensions._--Diameter of the outer shell 0.2, inner 0.16, distance of both 0.02; outer pores 0.03, inner 0.01.

_Habitat._--Central Pacific, Station 266, depth 2750 fathoms.

3. _Liosphæra porulosa_, n. sp.

Both shells with regular hexagonal pores; their number in the outer shell seven times as great as in the inner. Pores of the stout inner shell large, three times as broad as the bars, about eight on the quadrant. From each hexagon-corner arises one bristle-shaped radial beam; their distal ends are united by threads (three from each), forming the large meshes of the delicate outer shell. Each of these is divided by very thin threads into seven small circular porules, one central and six around it.

_Dimensions._--Diameter of the outer shell 0.25, inner 0.2, distance of both 0.025; outer pores 0.04, their porules 0.012, inner pores 0.15.

_Habitat._--Indian Ocean, Sunda Strait, Rabbe; surface.

Subgenus 2. _Craspedomma_, Haeckel.

_Definition._--Pores of both shells irregular, in each shell differing either in form or size.

4. _Liosphæra peridromium_, n. sp.

Both shells with the same number of large, polygonal, very irregular pores, exactly corresponding (about eight to ten on the quadrant); both with a very delicate thin framework. From the thread-like bars of the inner, very large and thin-walled, sphere arise perpendicularly innumerable short bristles of equal length, which are united at equal distances by tangential thread-like bars, parallel to the former, composing the outer shell. Each mesh is, therefore, surrounded by a delicate ballister or rail.

{78}_Dimensions._--Diameter of the outer shell 0.42, inner 0.4, distance of both 0.01; diameter of the meshes 0.02 to 0.06.

_Habitat._--North Pacific, Station 250, surface.

5. _Liosphæra polypora_, n. sp. (Pl. 20, fig. 2).

Both shells with small irregular roundish pores, of about the same size as the bars between them; twenty to thirty on the quadrant. The pores of the outer shell somewhat smaller, therefore much more numerous than the pores of the inner shell. Distance between the two shells about one-third as great as the radius of the inner. Both shells connected by numerous thin radial beams. Surface smooth or a little rough.

_Dimensions._--Diameter of the outer shell 0.18, inner 0.14, distance of both 0.02; pores and bars 0.003 to 0.005.

_Habitat._--West Tropical Pacific, Station 225, depth 4475.

Subfamily THECOSPHÆRIDA,[33] Haeckel, 1881, Prodromus, pp. 449, 452.

_Definition._--#Liosphærida# with three concentric spherical lattice-shells, which are united by radial beams.

Genus 21. _Thecosphæra_,[34] Haeckel, 1881, Prodromus, p. 452.

_Definition._--#Liosphærida# with two medullary (intracapsular) shells and one cortical (extracapsular) shell.

The genus _Thecosphæra_ comprises a large number of triple-shelled #Sphæroidea#, formerly united with _Actinomma_, but different from this genus in the absence of radial spines. The latticed shell is composed of three concentric spheres, two of which lie within the central capsule (medullary shells), and one outside (cortical shell). This latter is connected with the former by radial beams piercing the wall of the central capsule. From the following _Rhodosphæra_ (with one medullary and two cortical shells) _Carposphæra_ differs also by the distance of the three shells. In the former the distance between the two outer shells is much smaller, in the latter much larger, than the distance between the inner shells.

Subgenus 1. _Thecosphærantha_, Haeckel.

_Definition._--Pores of the cortical shell regular, hexagonal, or circular, with hexagonal frames or lobes, all of nearly equal size and form.

{79}1. _Thecosphæra triplodictyon_, n. sp.

Cortical shell thin walled, smooth, with regular, hexagonal pores, four times as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 8. Both medullary shells with regular circular pores, twice as broad as the bars, the inner half as broad as the outer. All three shells connected by six thin radial beams, opposite in pairs in the three dimensive axes.

_Dimensions._--Diameter of the outer shell 0.2, middle 0.05, inner 0.025; cortical pores 0.012, bars 0.003.

_Habitat._--Central Pacific, Station 271, surface.

2. _Thecosphæra phænaxonia_, n. sp.

Cortical shell thick walled, rough, with regular, circular, hexagonally framed pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 6. Both medullary shells with regular hexagonal pores and thin bars. All three shells connected by six prismatic radial beams, opposite in pairs in the three dimensive axes. (Shell similar to _Hexacontium sceptrum_, Pl. 24, fig. 1, 1_a_, but without external spines.)

_Dimensions._--Diameter of the outer shell 0.12, middle 0.04, inner 0.02; cortical pores 0.01, bars 0.005.

_Habitat._--North Pacific, Station 253, surface.

3. _Thecosphæra favosa_, n. sp.

Cortical shell thick walled, thorny, with regular, circular, hexagonally framed pores, of the same breadth as the bars. Radial proportion of the three spheres = 1 : 3 : 10. Both medullary shells with regular circular pores, connected with the former by twelve short prismatic, regularly disposed radial beams.

_Dimensions._--Diameter of the outer shell 0.2, middle 0.06, inner 0.02; cortical pores and bars 0.008.

_Habitat._--Central Pacific, Station 268, surface; also fossil in Barbados.

4. _Thecosphæra floribunda_, n. sp.

Cortical shell thick walled, smooth, with regular, elegantly six-lobed pores, three times as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 4. Both medullary shells with simple regular circular pores, connected with the former by six dimensive radial beams. (Similar to _Hexacontium floridum_, Pl. 24, fig. 4, but without external spines.)

_Dimensions._--Diameter of the outer shell 0.12, middle 0.06, inner 0.03; cortical pores 0.01, bars 0.0033.

_Habitat._--Central Pacific, Station 266, depth 2750 fathoms.

{80}Subgenus 2. _Thecosphærella_, Haeckel.

_Definition._--Pores of the cortical shell regular, circular, without hexagonal frames or lobes, all of nearly equal size and form.

5. _Thecosphæra inermis_, Haeckel.

_Actinomma inerme_, Haeckel, 1862, Monogr. d. Radiol., p. 440, Taf. xxiv.
fig. 5.

_Haliomma inerme_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss.
Berlin, p. 815.

Cortical shell thin walled, rough, with regular circular pores, twice as broad as the bars. Radial proportion of the three spheres and of their circular regular pores = 1 : 2 : 4. All three spheres connected by twelve regularly disposed radial beams.

_Dimensions._--Diameter of the outer shell 0.1, middle 0.05, inner 0.025; cortical pores 0.006, bars 0.003.

_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, at many Stations and at various depths.

6. _Thecosphæra æquorea_, Haeckel.

_Haliomma æquorea_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 83; Mikrogeol., 1854, Taf. xxii. fig. 35.

_Actinomma æquorea_, Haeckel, 1862, Monogr. d. Radiol., p. 443.

Cortical shell thick walled, smooth, with regular circular pores of the same breadth as the bars. Radial proportion of the three spheres and of their regular pores = 1 : 2 : 6 or = 1 : 3 : 9; they are connected by six radial beams, opposite by pairs in the three dimensive axes.

_Dimensions._--Diameter of the outer shell 0.08 to 0.12, middle 0.03 to 0.04, inner 0.09 to 0.12; cortical pores and bars about 0.006.

_Habitat._--Mediterranean, Corfu, surface; fossil in Greece and Sicily.

7. _Thecosphæra medusa_, Haeckel.

_Haliomma medusa_, Ehrenberg, 1838, Abhandl. d. k. Akad. d. Wiss. Berlin,
p. 130; Mikrogeol., 1854, Taf. xxii. figs. 33, 34.

_Actinomma medusa_, Haeckel, 1862, Monogr. d. Radiol., p. 444.

_Actinomma medusa_, Stöhr, 1880, Palæontogr., Bd. xxvi. p. 90, Taf. ii.
fig. 3.

Cortical shell thick walled, rough or thorny, with regular circular pores of the same breadth as the bars. Radial proportion of the three spheres = 1 : 2 : 4 (or 1 : 2.5 : 6); they are connected by four radial beams, crossed by pairs in two diameters, perpendicular one to another.

_Dimensions._--Diameter of the outer shell 0.08 to 0.12, middle 0.04 to 0.06, inner 0.02 to 0.025; cortical pores and bars in average 0.005.

_Habitat._--Fossil in Tertiary rocks of Barbados and the Mediterranean.

{81}8. _Thecosphæra entactinia_, n. sp.

Cortical shell thick walled, smooth, with regular circular pores of the same breadth as the bars. Radial proportion of the three spheres = 1 : 3 : 12; they are connected by very numerous (forty to fifty, or more) thin radial beams.

_Dimensions._--Diameter of the outer shell 0.24, middle 0.06, inner 0.02; cortical pores and bars 0.008.

_Habitat._--Central Pacific, Station 268, depth 2900 fathoms.

9. _Thecosphæra micropora_, n. sp.

Cortical shell thin walled, smooth, with very small and numerous, regular, circular pores, half as broad as the bars. Radial proportion of the three shells = 1 : 2 : 5; they are connected by twenty regularly disposed radial beams.

_Dimensions._--Diameter of the outer shell 0.2, middle 0.08, inner 0.04; cortical pores 0.002, bars 0.004.

_Habitat._--South Pacific, Station 288, surface.

Subgenus 3. _Thecosphærina_, Haeckel.

_Definition._--Pores of the cortical shell irregular polygonal, of unequal size or dissimilar form.

10. _Thecosphæra capillacea_, n. sp.

Cortical shell thin walled, smooth, with irregular polygonal pores, three to six times as broad as the bars. Both medullary shells with similar, but smaller, pores. Radial proportion of the three spheres = 1 : 3 : 8; they are connected by very numerous (sixty to eighty or more) thin radial beams. (Similar to _Actinomma capillaceum_, Pl. 29, fig. 6, but without external spines.)

_Dimensions._--Diameter of the outer shell 0.2, middle 0.075, inner 0.025; cortical pores 0.006 to 0.012, bars 0.002.

_Habitat._--North Pacific, Station 250, surface.

11. _Thecosphæra diplococcus_, n. sp.

Cortical shell thick walled, rough, with large irregular polygonal pores, two to three times as broad as the bars. Both medullary shells with small regular circular pores. Radial proportion of the three spheres = 1 : 2 : 6; they are connected by twenty (?) stout radial beams.

_Dimensions._--Diameter of the outer shell 0.12, middle 0.04, inner 0.02; cortical pores 0.008 to 0.012, bars 0.004.

_Habitat._--South Atlantic, Station 330, surface.

Subgenus 4. _Thecosphæromma_, Haeckel.

_Definition._--Pores of the cortical shell irregular, roundish, of unequal size or dissimilar form.

{82}12. _Thecosphæra dodecactis_, n. sp.

Cortical shell thin walled, smooth, with large irregular roundish pores, two to eight times as broad as the bars. Both medullary shells with regular circular pores, twice as broad as the bars. Radial proportion of the three spheres = 1 : 2 : 5; they are connected by twelve regularly disposed stout radial beams.

_Dimensions._--Diameter of the outer shell 0.2, middle 0.08, inner 0.04; cortical pores 0.004 to 0.016, bars 0.002.

_Habitat._--Central Pacific, Station 263, depth 2650 fathoms.

13. _Thecosphæra icosactis_, n. sp.

Cortical shell thin walled, with small irregular roundish pores, two to four times as broad as the bars. Both medullary shells with similar but smaller pores. Radial proportion of the three spheres = 1 : 3 : 8; they are connected by twenty thin radial beams.

_Dimensions._--Diameter of the outer shell 0.32, middle 0.12, inner 0.04; cortical pores 0.005 to 0.012, bars 0.003.

_Habitat._--North Pacific, Station 244, depth 2900 fathoms.

14. _Thecosphæra maxima_, n. sp.

Cortical shell thin walled, with small irregular roundish pores, two to six times as broad as the bars. Both medullary shells with similar, but smaller, pores. Radial proportion of the three spheres = 1 : 3 : 9; they are connected by numerous (forty to sixty or more) thin radial beams.

_Dimensions._--Diameter of the outer shell 0.45, middle 0.15, inner 0.05; cortical pores 0.008 to 0.024, bars 0.004.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

Genus 22. _Rhodosphæra_,[35] Haeckel, 1881, Prodromus, p. 452.

_Definition._--#Liosphærida# with one medullary (intracapsular) shell and two cortical (extracapsular) shells.

The genus _Rhodosphæra_ differs from the preceding _Thecosphæra_ in the same manner in which, among the Dyosphærida, _Liosphæra_ differs from _Carposphæra_. The cortical shell is double, composed of two not far distant shells, lying outside the central capsule. The distance between the shells is much smaller than the radius of the inner shell. This is connected by radial beams (piercing the central capsule) with the small central medullary shell.

Subgenus 1. _Rhodosphærella_, Haeckel.

_Definition._--Pores of both cortical shells regular, in each shell all of nearly equal size and form.

{83}1. _Rhodosphæra hexagonia_, n. sp.

Both cortical shells with the same number of regular hexagonal pores; the inner four times as broad as the bars, and half as broad as the outer pores, which are separated by thread-like bars. Medullary shell only one-fourth as broad as the inner cortical shell, with regular hexagonal pores of half the size. (Differs from the similar _Liosphæra hexagonia_, Pl. 20, fig. 3, by the possession of a medullary shell.)

_Dimensions._--Diameter of the outer shell 0.2, middle 0.16, inner 0.04; outer pores 0.013, middle 0.008, inner 0.004.

_Habitat._--Central Pacific, Station 266, depth 2750 fathoms.

2. _Rhodosphæra melitomma_, n. sp.

Both cortical shells with the same number of regular pores; the inner regular, circular, twice as broad as the bars, with elegant hexagonal frames and six roundish lobes alternating with the six radial spines which arise from the hexagon-corners; these short conical spines are connected at the distal end (at equal distances from the centre) by delicate threads (three from each spine), which form the delicate external shell. Medullary shell one-third as broad as the inner cortical shell, with small, simple, regular circular pores. (If in _Carposphæra melitomma_, Pl. 20, fig. 4, the distal ends of the spines became united by a cobweb-like outer shell, this species would be formed.)

_Dimensions._--Diameter of the outer shell 0.22, middle 0.18, inner 0.06; outer pores 0.025, middle 0.0125, inner 0.005.

_Habitat._--Central Pacific, Station 270, depth 2925 fathoms.

Subgenus 2. _Rhodosphæromma_, Haeckel.

_Definition._--Pores of both cortical shells irregular, in each shell of unequal size or dissimilar form.

3. _Rhodosphæra palliata_, n. sp.

Both cortical shells with an unequal number of irregular roundish pores; the outer pores somewhat smaller and much more numerous than the inner pores; the bars between the latter are thicker. Medullary shell about one quarter as broad as the inner cortical shell, with regular circular pores.

_Dimensions._--Diameter of the outer shell 0.4, middle 0.36, inner 0.08; outer pores on an average 0.008, middle 0.012, inner 0.004.

_Habitat._--Fossil in Barbados.

4. _Rhodosphæra pentaphylla_, n. sp.

Both cortical shells with unequal number of irregular roundish pores; the inner pores large, three to four times as broad as the bars; to each inner pore corresponds a group of five smaller {84}outer pores, like the five petals of a flower. Medullary shell half as broad as the inner cortical shell, with regular circular pores.

_Dimensions._--Diameter of the outer shell 0.25, middle 0.2, inner 0.1; outer pores on an average 0.006, middle 0.012, inner 0.004.

_Habitat._--Central Pacific, Station 268, depth 2900 fathoms.

Subfamily CROMYOSPHÆRIDA,[36] Haeckel, 1881, Prodromus, pp. 449, 453.

_Definition._--#Liosphærida# with four concentric spherical latticed shells, united by radial beams.

Genus 23. _Cromyosphæra_,[37] Haeckel, 1881, Prodromus, p. 453.

_Definition._--#Liosphærida# with two intracapsular (medullary) shells and two extracapsular (cortical) shells; the former united with the latter by radial beams piercing the wall of the central capsule.

The genus _Cromyosphæra_ is the only known genus of Cromyosphærida, or of such #Sphæroidea#, the smooth shell of which is composed of two medullary and two cortical shells. There may possibly be other Cromyosphærida, in which the shell is composed of one simple medullary and three cortical shells, or only of four extra-capsular cortical shells; but such have not as yet been observed. _Caryosphæra polysphærica_, Bütschli, 1882 (L. N. 41, Taf. xxiii. fig. 12) is probably a _Cromyosphæra_ (fossil in Barbados).

1. _Cromyosphæra quadruplex_, n. sp. (Pl. 30, fig. 9).

Radial proportion of the four spheres = 1 : 2 : 4 : 5. Outer cortical shell smooth, with large regular hexagonal pores, ten times as broad as the bars; inner cortical shell with irregular polygonal pores, five times as broad as the bars. Both medullary shells with regular circular pores of the same breadth as the bars.

_Dimensions._--Diameter of the four spheres--(A) 0.16, (B) 0.12, (C) 0.06, (D) 0.03.

_Habitat._--Central Pacific, Station 265, depth 2900 fathoms.

2. _Cromyosphæra rosetta_, n. sp.

Radial proportion of the four spheres = 1 : 2 : 8 : 10. Outer cortical shell smooth, with regular hexagonal pores and very thin bars; inner cortical shell with the same number of exactly corresponding, regular circular, hexagonally framed pores, twice as broad as the bars; the corners of the outer and inner hexagons united by radial bristles. Both medullary shells with regular circular pores, twice as broad as the bars.

_Dimensions._--Diameter of the four spheres--(A) 0.2, (B) 0.16, (C) 0.04, (D) 0.02.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

{85}3. _Cromyosphæra bigemina_, n. sp.

Radial proportion of the four spheres = 1 : 2 : 7 : 8. Outer cortical shell smooth, with regular hexagonal pores and very thin bars; inner cortical shell with the same number of exactly corresponding, regular circular pores. Both medullary shells with regular circular pores of the same breadth as the bars. (Somewhat similar to _Hexacromyon elegans_, Pl. 24, fig. 9, also with six inner radial beams, but without external radial spines.)

_Dimensions._--Diameter of the four spheres--(A) 0.2, (B) 0.17, (C) 0.05, (D) 0.025.

_Habitat._--North Pacific, Station 241, depth 2300 fathoms.

4. _Cromyosphæra cepa_, n. sp.

Radial proportion of the four spheres = 1 : 2 : 4 : 5. All four shells of the same structure, thick-walled, with regular circular pores, two to four times as broad as the bars; the size of the pores increases gradually from the inner to the outer shell. Surface thorny. Distance between the second and third shells twice as great as that between the others.

_Dimensions._--Diameter of the four spheres--(A) 0.125, (B) 0.1, (C) 0.05, (D) 0.025.

_Habitat._--Fossil in Barbados.

5. _Cromyosphæra scorodonium_, n. sp.

Radial proportion of the four spheres = 1 : 2 : 3 : 4. All four shells of the same structure, thin-walled, with irregular roundish pores, two to four times as broad as the bars; the size of the pores increasing gradually from the inner to the outer shell. Surface smooth. Distance between each two shells equal to the diameter of the innermost.

_Dimensions._--Diameter of the four spheres--(A) 0.12, (B) 0.09, (C) 0.06, (D) 0.03.

_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.

6. _Cromyosphæra antarctica_, n. sp..

Radial proportion of the four spheres = 1 : 2 : 5 : 7. Both cortical shells with irregular polygonal roundish pores; the outermost with thinner bars and rough surface, the inner with thicker bars. Both medullary shells with irregular roundish pores.

_Dimensions._--Diameter of the four spheres--(A) 0.18, (B) 0.12, (C) 0.05, (D) 0.025.

_Habitat._--Antarctic Ocean; in very large number, together with _Rhizosphæra antarctica_, in the diatomaceous ooze of Station 157 (3rd March 1874); depth 1950 fathoms.

Subfamily CARYOSPHÆRIDA,[38] Haeckel, 1881, Prodromus, pp. 449, 454.

_Definition._--#Liosphærida# with numerous (five or more) concentric spherical latticed shells, united by radial beams.

{86}Genus 24. _Caryosphæra_,[39] Haeckel, 1881, Prodromus, p. 454.

_Definition._--#Liosphærida# with two intracapsular (medullary) shells and three or more extracapsular (cortical) shells; the former united with the latter by radial beams piercing the wall of the central capsule.

The genus _Caryosphæra_, the only observed form of this subfamily, comprises those #Liosphærida# in which the shell is composed of two medullary and three or more cortical shells. Such forms (without radial spines) are very rare; I observed only two species, one with five, the other with six shells. They are derived from _Cromyosphæra_ by further apposition of outer cortical shells.

1. _Caryosphæra pentalepas_, n. sp.

Shell composed of five concentric spheres, with radial proportion = 1 : 2 : 8 : 10 : 12. Both medullary shells with regular circular pores, twice as broad as the bars. First cortical shell with regular, circular, hexagonally framed pores, three times as broad as the bars; second cortical shell with regular hexagonal pores, four times as broad as the bars; third (outermost) cortical shell with regular hexagonal pores and very thin thread-like bars. Surface smooth.

_Dimensions._--Diameter of the five shells--(A) 0.02, (B) 0.04, (C) 0.16, (D) 0.2, (E) 0.24.

_Habitat._--Central Pacific, Station 274, depth 2750 fathoms.

2. _Caryosphæra hexalepas_, n. sp.

Shell composed of six concentric spheres, with the radial proportion = 1 : 2 : 4 : 5 : 6 : 8. All six shells with regular circular pores, two to four times as broad as the bars, with increasing size from the centrum against the smooth surface.

_Dimensions._--Diameter of the six shells--(A) 0.025, (B) 0.05, (C) 0.1, (D) 0.13, (E) 0.16, (F) 0.2.

_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.

Subfamily PLEGMOSPHÆRIDA,[40] Haeckel, 1881, Prodromus, p. 455.

_Definition._--#Liosphærida# with spongy spherical shell, with or without latticed medullary shell in the centre.

Genus 25. _Styptosphæra_,[41] Haeckel, 1881, Prodromus, p. 455.

_Definition._--#Liosphærida# forming a solid sphere of spongy framework, without enclosed medullary shell, and without central cavity.

{87}The genus _Styptosphæra_ presents a spherical shell with smooth or rough surface (without radial spines), the whole mass of which is composed of looser or denser spongy wicker-work.

1. _Styptosphæra spumacea_, n. sp.

Spongy framework of the solid sphere loose, with large polygonal meshes of slightly different size, ten to twenty times as broad as the bars. Structure of the whole spongy sphere the same. Central capsule filled with crystals. Surface smooth.

_Dimensions._--Diameter of the sphere 0.32, of the central capsule 0.26, meshes 0.01 to 0.02, bars 0.001.

_Habitat._--North Pacific, Station 236, surface.

2. _Styptosphæra spongiacea_, n. sp.

Spongy framework in the central part of the solid sphere much more compact than in the peripheral part, becoming gradually looser towards the rough surface. Meshes in the centre three to five times, in the periphery fifteen to twenty times as broad as the bent bars.

_Dimensions._--Diameter of the sphere 0.45, inner meshes 0.006 to 0.01, outer meshes 0.03 to 0.04, bars 0.002.

_Habitat._--Central Pacific, Station 271, surface.

3. _Styptosphæra stupacea_, n. sp.

Spongy framework of the solid sphere rather compact, everywhere of the same structure, with roundish, nearly equal meshes, six to eight times as broad as the bars. Surface rough with prominent thorns.

_Dimensions._--Diameter of the sphere 0.22, meshes 0.01 to 0.012, bars 0.0015.

_Habitat._--South Pacific, Station 291, surface.

Genus 26. _Plegmosphæra_, Haeckel,[42] 1881, Prodromus, p. 455.

_Definition._--#Liosphærida# forming a hollow sphere of spongy framework, without a medullary shell in the central cavity.

The genus _Plegmosphæra_ develops a large hollow sphere, the wall of which is composed of looser or denser spongy wicker-work. On the inner as well as on the outer face of the spongy shell-wall may be present a simple lattice-sphere from which the threads of the framework arise; but in some species these lattice-plates are quite absent.

{88}Subgenus 1. _Plegmosphærantha_, Haeckel.

_Definition._--Inside and outside of the spongy shell-wall smooth, closed by a lattice-plate with polygonal meshes.

1. _Plegmosphæra maxima_, n. sp.

Radius of the spherical shell-cavity eight to ten times as great as the thickness of the thin spongy wall. Inside and outside of the wall smooth, closed by a lattice-plate with irregular polygonal meshes. Only three or four meshes in the thickness of the wall.

_Dimensions._--Diameter of the spongy sphere 0.8 to 1.0 mm., of its inner cavity 0.7 to 0.8, meshes 0.01 to 0.02, bars 0.002 to 0.003, central capsule 0.5 to 0.6, nucleus 0.1 to 0.15.

_Habitat._--Central Pacific, Station 271, surface.

2. _Plegmosphæra coelopila_, n. sp.

Radius of the spherical shell-cavity eight to ten times as great as the thickness of the spongy wall. Inside and outside of the wall closed by a smooth lattice-plate with irregular polygonal meshes, five to ten times as broad as the bars.

_Dimensions._--Diameter of the shell 0.32, of its cavity 0.26, meshes 0.01 to 0.02, bars 0.002.

_Habitat._--North Atlantic, Færöe Channel, Gulf Stream, John Murray.

3. _Plegmosphæra pachypila_, n. sp.

Radius of the spherical shell-cavity about equal to the thickness of the spongy wall. Inside and outside of the wall closed by a smooth lattice-plate with irregular polygonal meshes, three to six times as broad as the bars.

_Dimensions._--Diameter of the shell 0.24, of its cavity 0.12.

_Habitat._--North Pacific, Station 250, surface.

Subgenus 2. _Plegmosphærella_, Haeckel.

_Definition._--Inside of the spongy shell-wall closed by a smooth lattice-plate, outside rough, spongy, with prominent thorns.

4. _Plegmosphæra entodictyon_, n. sp.

Radius of the spherical shell-cavity half as great as the thickness of the spongy wall. Inside of the wall closed by a smooth lattice-plate, outside rough, spongy.

_Dimensions._--Diameter of the shell 0.24, of its cavity 0.08.

_Habitat._--South Pacific, Station 300, surface.

{89}5. _Plegmosphæra leptodictyon_, n. sp.

Radius of the spongy shell-cavity six times as great as the thickness of the spongy wall. Inside of the wall closed by a smooth lattice-plate, outside rough spongy.

_Dimensions._--Diameter of the shell 0.44, of its cavity 0.36.

_Habitat._--Central Pacific, Station 266, surface.

Subgenus 3. _Plegmosphæromma_, Haeckel.

_Definition._--Inside of the spongy shell-wall rough spongy, without lattice-plate, outside closed by a smooth lattice-plate.

6. _Plegmosphæra exodictyon_, n. sp. (Pl. 18, fig. 8).

Radius of the spongy shell-cavity only one-fourth as great as the thickness of the spongy shell-wall. Outside of the wall closed by a smooth lattice-plate, inside rough, spongy.

_Dimensions._--Diameter of the shell 0.4, of its cavity 0.08.

_Habitat._--South Atlantic, Station 325, surface.

Subgenus 4. _Plegmosphærusa_, Haeckel.

_Definition._--Inside and outside of the spongy shell-wall rough, with spongy or spiny surface, without lattice-plate.

7. _Plegmosphæra leptoplegma_, n. sp.

Radius of the spherical shell-cavity half as great as the thickness of the loose spongy shell-wall. Inside and outside of the wall rough spongy, not closed by a lattice-plate. Meshes ten to twenty times as broad as the bars.

_Dimensions._--Diameter of the shell 0.3, of its cavity 0.088.

_Habitat._--North Atlantic, Station 253, surface.

8. _Plegmosphæra pachyplegma_, n. sp.

Radius of the spherical shell-cavity about equal to the thickness of the dark and dense spongy shell-wall. Inside and outside of the wall rough spongy, not closed by a lattice-plate. Meshes three to five times as broad as the bars.

_Dimensions._--Diameter of the shell 0.2, of its cavity 0.1.

_Habitat._--Central Pacific, Station 270, surface.

Genus 27. _Spongoplegma_,[43] Haeckel, 1881, Prodromus, p. 455.

_Definition._--#Liosphærida# forming a sphere of spongy framework, which encloses in the centre one single latticed medullary shell.

{90}The genus _Spongoplegma_ may be regarded as a _Carposphæra_, in which the simple latticed cortical shell is represented by an irregular spongy framework, immediately enclosing the simple latticed medullary shell.

1. _Spongoplegma antarcticum_, n. sp.

Cortical shell with loose spongy framework and rough surface, four to six times as broad as the enclosed simple medullary shell. Pores of the latter regular circular, twice as broad as the bars. From its surface arise numerous (forty to fifty or more) short radial beams, which become forked and compose, by communication of lateral branches, the spongy cortical shell.

_Dimensions._--Diameter of the spongy cortical shell 0.2 to 0.3 of the latticed medullary shell 0.05 to 0.06.

_Habitat._--Antarctic Ocean, in large number, together with _Cromyosphæra antarctica_; in the Diatom ooze of Station 157 (depth 1950 fathoms).

Genus 28. _Spongodictyon_,[44] Haeckel, 1862, Monogr. d. Radiol., p. 459.

_Definition._--#Liosphærida# forming a sphere of spongy framework, which encloses in the centre a double latticed concentric medullary shell.

The genus _Spongodictyon_ can be regarded as a _Thecosphæra_, in which the simple latticed cortical shell is represented by an irregular spongy framework, which immediately encloses the double latticed medullary shell. Sometimes this latter appears triple, the inner surface of the spongy cortical shell forming a smooth spherical lattice-plate, separated by an interval from the double medullary shell.

Subgenus 1. _Dictyoplegma_, Haeckel, 1862, Monogr. d. Radiol, p. 458.

_Definition._--Spongy cortical shell enveloping immediately the double medullary shell.

1. _Spongodictyon spongiosum_, Haeckel.

_Dictyosoma spongiosum_, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 31, Taf. ii. figs. 9-11.

_Dictyoplegma spongiosum_, Haeckel, 1862, Monogr. d. Radiol., p. 458.

Spongy framework of the cortical shell loose, with large, polygonal roundish meshes, on an average as large as the double medullary shell, which is immediately enveloped by it. Both concentric medullary shells with subregular roundish pores, twice as broad as the bars.

_Dimensions._--Diameter of the cortical shell 0.2 to 0.3 or more; of the outer medullary shell 0.03, inner 0.01.

_Habitat._--Mediterranean (French south coast, surface), J. Müller.

{91}2. _Spongodictyon cavernosum_, n. sp.

Spongy framework of the cortical shell rather compact in the inner part, which immediately envelops the double medullary shell; very loose, with large caverns in the outer part, caverns of the surface larger than the medullary shell. Both medullary shells with regular circular pores, three times as broad as the bars.

_Dimensions._--Diameter of the cortical shell 0.3 to 0.4, outer medullary shell 0.1, inner 0.03.

_Habitat._--Tropical Atlantic, Station 338, surface.

Subgenus 2. _Spongodictyoma_, Haeckel.

_Definition._--Spongy cortical shell on the inner surface with a smooth lattice-plate (or third medullary shell), which is connected by radial beams with the inner double medullary shell.

3. _Spongodictyon trigonizon_, Haeckel.

_Spongodictyon trigonizon_, Haeckel, 1862, Monogr. d. Radiol., p. 459,
Taf. xxvi. figs. 4-6.

_Dictyosoma trigonizon_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d.
Wiss. Berlin, p. 841.

Spongy framework of the cortical shell very loose, with very large, for the most part triangular meshes, which are two to six times as large as the enclosed double medullary shell. From the surface of the latter arise numerous radial beams, which are connected by a spherical lattice-plate, forming the smooth inner surface of the spongy sphere (or a third medullary shell). The structure of the framework reminds one of the PHÆODARIUM _Sagena_ (Pl. 108). Pores of both medullary shells regular circular, twice as broad as the bars.

_Dimensions._--Diameter of the cortical shell 0.5 to 1.15, outer medullary 0.05, inner 0.035.

_Habitat._--Mediterranean, Messina, surface.

4. _Spongodictyon arcadophoron_, n. sp.

Spongy framework of the cortical shell in the inner part very loose, in the outer part more compact; outer meshes scarcely as large as the inner medullary shell (or only half as large), inner meshes two to four times as large. From the surface of the double medullary shell arise numerous radial beams, which are forked at equal distances from the centre; the fork branches are curved and united together by dichotomous branches, like elegant arcades; and these arcades form together the large polygonal meshes on the inside of the cortical shell (or a third medullary shell). Both medullary shells with regular circular pores, of the same breadth as the bars.

_Dimensions._--Diameter of the cortical shell 0.2, outer medullary shell 0.04, inner 0.02.

_Habitat._--Tropical Atlantic, Station 349, surface.

{92}Family VI. #COLLOSPHÆRIDA#, J. Müller[45] (Pls. 5-8).

_Definition._--#Sphæroidea# living associated in colonies, united by an alveolar jelly-body, and connected by the network of anastomosing pseudopodia.

The family #Collosphærida# comprises all polyzous or social #Sphæroidea#, and constitutes the only polyzoic group among the SPHÆRELLARIA. This group was first constituted by J. Müller as "_Radiolaria polyzoa_ with shells."[46] Formerly following his authority, in my Monograph I had separated them from the other #Sphæroidea# and united them with the social Collodaria (Sphærozoida).[47] Also R. Hertwig in his Organismus der Radiolarien[48] united them with his Sphærozoea. In my Prodromus[49] I had retained this isolated position. But a further careful study has convinced me that this isolation is not truly natural, and that the Collosphærida are only "social Ethmosphærida" which have arisen from this solitary subfamily by adaptation to colonial life. There are some forms of Collosphærida which are nearly identical with some forms of Ethmosphærida, only differing from the latter by their association in colonies; and in some forms of both groups it is quite impossible to decide whether the isolated shells appertain to one or to the other family.

The isolated shell of the Collosphærida is almost constantly (with few exceptions) a simple extracapsular lattice-shell, as in the Monosphærida; only the small group of Clathrosphærida (with the genera _Clathrosphæra_ and _Xanthiosphæra_) exhibit an exception, the simple lattice-shell being overgrown by an external mantle or veil of very thin, cobweb-like, irregular lattice-work (Pl. 8, figs. 6-11). Therefore these Clathrosphærida bear to the Acrosphærida (or the common simple Collosphærida) a relation similar to that which _Liosphæra_ (p. 76) bears to _Cenosphæra_; both shells are extracapsular "cortical shells" at a very short distance apart. In the Collosphærida true concentric medullary shells never occur; the central capsule always lies quite freely in the simple or double cortical shell, separated from it by a jelly-veil.

Although a well marked difference in the simple lattice-shell of the social Collosphærida and the solitary Ethmosphærida does not exist, nevertheless in most cases the two shells can be distinguished by a practiced observer. The simple fenestrated shells of the monozoic Ethmosphærida are commonly quite regular spheres in a mathematical sense, or regular "endospherical polyhedra"; whereas in the Collosphærida they are commonly more or less irregular, often to an extraordinary degree (Pls. 5-8). Some species of Collosphærida, however, also possess quite regular spherical shells. Another difference is often shown in the lattice-work of the shells, which in the Collosphærida is nearly always very irregular, and exhibits a peculiar tendency to the {93}production of radial, conical, or cylindrical tubules. These occur as well on the inside as on the outside of the shell, and the tubules are now more conical, now more cylindrical; their wall either solid or pierced by pores (Pls. 5-8). The tubules are commonly very irregular in form, size, and disposition; distinguished, however, by a number of hereditary peculiarities, which are sufficient for the distinction of genera. Similar tubules occur also in some genera of solitary Ethmosphærida (_Coscinomma_, _Ethmosphæra_, _Conosphæra_, &c., Pl. 12); but the tubules are here much more regular and not so highly developed.

Besides the tubules of the fenestrated shells, in some genera of Collosphærida the surface is armed with irregular thorns, rarely with more regular radial spines. But these spines obtain constantly the character of accessory by-spines, and remain short and thin. In this family typical radial spines never occur in a regular and characteristic disposition, corresponding to dimensive axes, as is the case in nearly all solitary #Sphæroidea#, only excepting the Liosphærida. Commonly these spines or thorns serve as protective arms for the shell-meshes, surrounding them often in the form of coronels. Often the lattice-plate of the irregular roundish shell is tubercular, elevated into irregular protuberances, bearing on the top a short spine or thorn (Pl. 8).

The _Central Capsule_ of the Collosphærida is always a regular sphere, as in all other #Sphæroidea#; it is constantly placed within the lattice-shell, and commonly much smaller than it, separated from it by a thick jelly-veil. A remarkable difference from the solitary #Sphæroidea# is shown in the early division of the nucleus. Commonly the central capsule of the Collosphærida contains in its centre a large oil-globule, surrounded by very numerous small nuclei. R. Hertwig estimated this difference as so important, that he separated the social "Sphærozoea" and the solitary "Peripylea" as two different orders. As already shown above (p. 7, 24), we cannot support this separation, and are now convinced that this difference in the development of the spores--just as in the #Collodaria#--is the consequence of an adaptation to social life.

The common jelly-body, in which the numerous central capsules and their enveloping shells are united, exhibits in the Collosphærida quite the same characters as in the other social Radiolaria, the Collozoida and Sphærozoida. The jelly-body is very voluminous, commonly spherical, often cylindrical, of considerable size; constantly containing numerous large alveoles. Often each shell is enclosed in a separate alveole with rather solid wall (Pl. 6, fig. 2). Sometimes in the dead colonies all shells are united in the central part of the jelly-body, whilst its peripheral part is composed of a stratum of large alveoles (Pl. 8, fig. 11); at other times no alveoles are visible (Pl. 7, fig. 11). In many living colonies I found a very large spherical alveole with thick wall in the centre of the spherical colony, surrounded by many strata of delicate thin-walled alveoles (Pl. 5, fig. 1). In this case often the inner younger capsules were naked, {94}without shells, the outer only surrounded by shells. Already in my Monograph I had described the same peculiar formation.[50]

_Synopsis of the Genera of Collosphærida._

-------------------------------------------------------------------------
I. Subfamily Acrosphærida. (Lattice-shell simple, without an external
mantle of network.)
-------------------------------------------------------------------------
{Inside {Inside smooth, 29. _Collosphæra_.
Outside of { without {
the shell { tubuli. {Inside spiny, 30. _Tribonosphæra_.
smooth, {
without { {Tubuli
spines or {Inside with { imperforated, 31. _Pharyngosphæra_.
tubuli. { centripetal {
{ tubuli. {Tubuli
{ { fenestrated, 32. _Buccinosphæra_.

{Spines
{ irregularly
{ scattered on
{ the surface, 33. _Acrosphæra_.
{
Outside of the shell armed {Each larger
with solid spines, but { pore with one
with hollow tubuli. { single spine, 34. _Odontosphæra_.
{
{Each larger
{ pore with
{ a coronal of
{ spines, 35. _Choenicosphæra_.

{Mouth of the
{ tubuli
{ truncated,
{ smooth, 36. _Siphonosphæra_.
{
Outside of {Tubuli {Mouth with
the shell { simple, not { one single
with { branched. { large tooth, 37. _Mazosphæra_.
irregular { {
radial { {Mouth with a
tubuli, { { coronal of
the wall of { { teeth, 38. _Trypanosphæra_.
which is {
solid, not {Tubuli irregularly branched,
fenestrated.{ each with two to four or
{ more openings, 39. _Caminosphæra_.

{Mouth of the
{ tubuli
{ truncated,
{ smooth, 40. _Solenosphæra_.
Outside of the shell with {
irregular radial tubuli, {Mouth with one
open on both ends, { single large
with fenestrated wall. { tooth, 41. _Otosphæra_.
{
{Mouth with a
{ coronal of
{ teeth, 42. _Coronosphæra_.
-------------------------------------------------------------------------
II. Subfamily Clathrosphærida. (Lattice-shell double, with an external
mantle of network.)
-------------------------------------------------------------------------
Surface of the outer shell smooth, 43. _Clathrosphæra_.

Surface of the outer shell thorny, 44. _Xanthiosphæra_.

Subfamily ACROSPHÆRIDA, Haeckel, 1881, Prodromus, p. 471.

_Definition._--#Collosphærida# with one simple lattice-shell around every central capsule of the coenobium.

{95}Genus 29. _Collosphæra_,[51] J. Müller, 1855.

_Definition._--#Collosphærida# with simple shells, smooth on the inside and on the outside, without any spines or tubuli.

The genus _Collosphæra_ is the most simple form of all Collosphærida, and must be regarded as the common ancestral form of this family. As the lattice-shell is quite a simple sphere, without any spines, tubules, or other peculiar productions, it agrees perfectly with _Cenosphæra_, and represents the social or polyzoid aggregate of this solitary or monozoid genus. Therefore a certain distinction between the isolated shells of the two genera is often very difficult or even impossible; but commonly this distinction is possible owing to the circumstance, that in the majority of the _Collosphæræ_ the shell is more or less irregular roundish or polyhedral, not quite spherical, as in _Cenosphæra_. _Dermatosphæra_, Ehrenberg, is a _Collosphæra_ with small pores (compare L. N. 16, p. 533).

Subgenus 1. _Eucollosphæra_, Haeckel.

_Definition._--Shell a regular or subregular sphere.

1. _Collosphæra primordialis_, n. sp.

Shell a regular sphere, with very delicate and regular network of hexagonal meshes. Six to eight meshes in the half meridian of the shell. Diameter of the meshes ten to fifteen times as broad as the thin bars between them. Can be regarded as social form of _Cenosphæra primordialis_.

_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.008.

_Habitat._--Central Pacific, Stations 271 to 274, surface.

2. _Collosphæra regularis_, n. sp.

Shell a regular sphere, with a perfectly regular network of circular meshes, all of the same size. Ten to twelve meshes in the half meridian of the shell. Diameter of the meshes the same as that of the bars between them.

_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.005 to 0.006.

_Habitat._--Indian Ocean, Madagascar, surface, Rabbe.

3. _Collosphæra globularis_, n. sp.

Shell a regular sphere, with subregular network of circular meshes of different sizes; few large pores between many smaller pores. Ten to twenty meshes in the half meridian of the shell. Diameter of the meshes from half to twice as broad as that of the bars.

{96}_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.002 to 0.008, breadth of the bars 0.004 to 0.008.

_Habitat._--Tropical and subtropical zone of both hemispheres, widely distributed; Canaries, Azores, Cape Verde Islands, Guinea Coast, Brazil Coast, Indian Ocean, Madagascar, Ceylon, surface.

Subgenus 2. _Dyscollosphæra_, Haeckel.

_Definition._--Shell not a regular sphere, but irregular roundish, in all degrees of variation between subspherical and polyhedral or quite irregular forms.

4. _Collosphæra huxleyi_, J. Müller.

_Collosphæra huxleyi_, J. Müller, 1855, Abhandl. d. k. Akad. d. Wiss.
Berlin, pp. 55-59, Taf. viii. figs. 6-9.

_Collosphæra huxleyi_, Haeckel, 1862, Monogr. d. Radiol., p. 534, Taf.
xxxiv.

_Collosphæra huxleyi_, Cienkowski, 1871, Archiv f. mikrosk. Anat., Bd.
vii. p. 374, Taf. xxix. figs. 1-6.

_Collosphæra ligurina_, J. Müller, 1856, Monatsber. d. k. Akad. d. Wiss.
Berlin, p. 481.

_Thalassicolla punctata_, var., Huxley, 1851, Ann. and Mag. Nat. Hist.,
ser. 2, vol. viii. p. 434, pl. xvi. fig. 6.

Shell subspherical, somewhat irregular, sometimes with more or less superficial impressions, with irregular network of roundish meshes. Eight to sixteen meshes in the half meridian of the shell, one to three times as broad as their bars. Very variable, with direct transition-forms to other species of this genus, especially to _Collosphæra globularis_, _Collosphæra tuberosa_, _Collosphæra pyriformis_, and _Collosphæra polyedra_.

_Dimensions._--Diameter of the shell 0.1 to 0.16, of the pores 0.004 to 0.012, of the bridges 0.003 to 0.006.

_Habitat._--Cosmopolitan; common in the greater part of the warmer seas, surface.

5. _Collosphæra polygona_, n. sp. (Pl. 5, fig. 13).

_Collosphæra huxleyi_ var., Haeckel, 1862, Monogr. d. Radiol., Taf.
xxxiv. fig. 5.

Shell irregular polygonal, with very delicate, irregular network of polygonal meshes, four to twelve times as broad as the bars. Ten to twenty pores on the half meridian of the shell.

_Dimensions._--Diameter of the shell 0.1 to 0.2, of the pores 0.012 to 0.004, of the bars 0.001 to 0.002.

_Habitat._--Mediterranean, Atlantic, surface; Stations 348 to 354.

6. _Collosphæra pyriformis_, Haeckel, n. sp.

Shell irregular, rounded, ovate or pear-shaped, with irregular network of rounded or nearly polygonal meshes. Ten to twenty meshes in the half meridian of the shell, one to three times as broad as the bars. Commonly one large opening (two to three times as broad as the largest {97}meshes) on the thinner end of the ovate shell (corresponding to the insertion of a pear-stalk); sometimes two or three such large openings.

_Dimensions._--Diameter of the shell 0.1 to 0.15, of the pores 0.008 to 0.016, of the bridges 0.004 to 0.008.

_Habitat._--Tropical zone--Cape Verde Islands, Ceylon; Central Pacific, Stations 266 to 272, 348 to 352, &c.

7. _Collosphæra polyedra_, n. sp.

_Trisolenia zanguebarica_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 301, Taf. x. fig. 11.

Shell irregular, polyhedral, with even or somewhat vaulted sides, and obtuse ridges between them. Network more or less irregular, with small rounded meshes, quite as broad or twice as broad as their bars. Besides these small pores constantly some large round openings (commonly three to six), situated on the corners of the polyhedral shell, four to six times as large as the pores. Often an acute tooth on the edge of each large opening. Transition-form between _Collosphæra_ and _Solenosphæra_ or _Odontosphæra_.

_Dimensions._--Diameter of the shell 0.1 to 0.15, of the pores 0.004 to 0.008, of their bridges 0.004, of the large openings 0.24 to 0.032.

_Habitat._--Tropical zone of the Pacific and the Indian Ocean; Stations 266 to 272, surface.

8. _Collosphæra tuberosa_, n. sp.

_Collosphæra huxleyi_, var., Haeckel, 1862, Monogr. d. Radiol., Taf.
xxxiv. figs. 3, 9.

Shell very irregular, between subspherical and polyhedral in form, but always with irregular impressions, boils or bosses, and between these different rounded prominent tubercles and ridges. Network irregular, strong, with rounded, subcircular or nearly polygonal meshes. Ten to thirty pores in the half meridian of the shell. Diameter of the meshes half to four times as broad as that of the thick bars.

_Dimensions._--Diameter of the shell very variable in the same coenobium, 0.05 to 0.2, of the pores 0.002 to 0.008, breadth of the bridges 0.004 to 0.006.

_Habitat._--Cosmopolitan, common in all warmer seas, surface.

9. _Collosphæra irregularis_, n. sp.

_Collosphæra huxleyi_, var., Haeckel, 1862, Monogr. d. Radiol., Taf.
xxxiv. fig. 8.

Shell quite irregular, knotty or bulbous, with irregular impressions, and prominent knobs or bulbs between them. Network thin, fragile, quite irregular, with polygonal meshes of most unequal size and form. Five to twenty pores in the half meridian of the shell. Diameter of the meshes two to ten times as broad as that of the thin bars.

_Dimensions._--Diameter of the shell very variable in the same coenobium, 0.04 to 0.24, of the pores 0.005 to 0.05, of the bridges 0.002 to 0.004.

_Habitat._--Mediterranean, Atlantic, not common; Stations 348, 352, &c., surface.

{98}Genus 30. _Tribonosphæra_,[52] Haeckel, 1881, Prodromus, p. 471.

_Definition._--#Collosphærida# with simple shells, on the inside with radial centripetal beams.

The genus _Tribonosphæra_ differs from _Collosphæra_ by a very peculiar and rare character, the development of centripetal radial sticks on the internal face of the shell; these beams are not united in the centrum, but finish freely in a certain distance from it.

1. _Tribonosphæra centripetalis_, n. sp. (Pl. 5, fig. 12).

Shell roundish or subspherical, with numerous small circular or roundish pores, about twice as broad as the bars. Twenty to thirty pores on the half meridian of the shell. Outside of the shell smooth, inside a variable number (ten to twenty) of thin, radial, centripetal sticks or spines, one-third or one-half as long as the radius of the shell. (In the central capsule many very large crystals, resting after the destruction of the capsule.)

_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.003 to 0.005, of the bridges 0.001 to 0.002; length of the inner centripetal sticks 0.02 to 0.03.

_Habitat._--Central Pacific, Station 271, surface.

Genus 31. _Pharyngosphæra_,[53] n. gen.

_Definition._--#Collosphærida# with simple shells, having on the inside radial centripetal tubes, the walls of which are solid.

The genus _Pharyngosphæra_ differs from _Collosphæra_ by the development of radial tubules on the inside of the shell, which are directed centripetally towards its centre. The wall of the tubule is solid, not latticed as in the following genus.

1. _Pharyngosphæra stomodæa_, n. sp. (Pl. 5, fig. 10).

Shell irregular polyhedral, with ten to fifteen polygonal faces and rounded edges. Pores very small, circular, irregularly scattered, smaller than the bars. Twelve to fifteen pores on the half meridian of the shell. On the inside of every shell-face one short, nearly cylindrical, centripetal tubule, twice as long as broad, and about one-third as long as the shell radius. Outer umbilical mouth of the tubules somewhat wider than the inner truncated mouth.

_Dimensions._--Diameter of the shell 0.11 to 0.12, of the pores 0.003 to 0.005, of the bars 0.01 to 0.02; length of the inner tubuli 0.02, breadth of them 0.01.

_Habitat._--South Pacific, Station 288, depth 2600 fathoms.

{99}Genus 32. _Buccinosphæra_,[54] n. gen.

_Definition._--#Collosphærida# with simple shells, having on the inside radial centripetal tubes, the walls of which are fenestrated.

The genus _Buccinosphæra_ exhibits, on the inner surface of the shell, radial centripetal tubules similar to those of the foregoing _Pharyngosphæra_; but the walls of these tubes are here latticed, not solid; they represent therefore true invaginations of the whole shell-wall.

1. _Buccinosphæra invaginata_, n. sp. (Pl. 5, fig. 11).

Shell irregular roundish or nearly polyhedral, with a variable number of umbilical depressions, which are prolonged on the inside into cylindrical or somewhat conical, centripetal, fenestrated tubes, about one-third as long as the shell radius. Inner mouth of the tubes narrower, scarcely half as broad as the outer mouth, about equal to one-fourth the shell radius, truncated. Pores of the tubes and of the shell small, roundish, irregular in size and distribution, about as broad as the bars. Twenty-five to thirty pores in the half meridian of the shell. In all observed specimens the spherical central capsule (half as broad as the shell) contained a large number of crystals.

_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.001 to 0.003, of the bars 0.002 to 0.003; length of the tubuli 0.02; outer mouth 0.026, inner mouth 0.013; crystals in the central capsule 0.002 to 0.004, sometimes 0.008.

_Habitat._--Philippine Islands (Samboangan), Station 213, surface.

2. _Buccinosphæra tubaria_, n. sp.

Shell irregular polyhedral with rounded edges, with a variable number of umbilical depressions, which are prolonged on the inside into large, nearly cylindrical, centripetal, fenestrated tubes, half as long as the shell radius. In the middle the tubes are somewhat constricted and narrower. Inner mouth of the tubes dilated, nearly as broad as the outer mouth, about equal to one-half the shell-radius, truncated. Pores of the tubes and of the shell large, roundish polygonal, irregular in size and distribution, three to four times as broad as the bars. Fifteen to twenty pores in the half meridian of the shell.

_Dimensions._--Diameter of the shell 0.12 to 0.14, of the pores 0.008 to 0.012, of the bars 0.002 to 0.004; length of the tubuli 0.03; outer mouth 0.04, inner mouth 0.03.

_Habitat._--North coast of New Guinea, Station 217, surface.

Genus 33. _Acrosphæra_,[55] Haeckel, 1881, Prodromus, p. 471.

_Definition._--#Collosphærida# with simple shells, the outer surface of which is covered with radial, irregularly scattered spines.

{100}The genus _Acrosphæra_ differs from its ancestral genus _Collosphæra_ by the development of spines on the outer surface of the shell. These are either short, straight, radial spines, or oblique and often curved; their base is often inflated; they are irregularly scattered on the whole surface between the pores.

1. _Acrosphæra erinacea_, n. sp.

Shell a regular sphere, everywhere covered with small, very numerous, straight radial spines, regularly scattered between the pores. In the half meridian of the shell ten to twelve circular pores, all of the same form and size, double as broad as the bars. Spines bristle-shaped, very thin, solid, about as long as the diameter of the pores.

_Dimensions._--Diameter of the shell 0.1 to 0.12, of the pores 0.008 to 0.012; length of the spines 0.01.

_Habitat._--Tropical zone of the Atlantic, coast of Brazil, Rabbe, surface.

2. _Acrosphæra echinoides_, n. sp. (Pl 8, fig. 1).

Shell a regular sphere, covered with numerous, straight, radial spines, irregularly scattered over the whole surface. In the half meridian of the shell twenty to thirty irregular roundish pores of variable size, one to four times as broad as the bars. Spines conical, strong, quite radial, at the top of small conical elevations, which are perforated by from three to six pores.

_Dimensions._--Diameter of the shell 0.12 to 0.15, of the pores 0.002 to 0.008; length of the spines 0.015, of their basal zones 0.01.

_Habitat._--South-east corner of the Pacific, Valparaiso, Station 298, surface.

3. _Acrosphæra setosa_, Haeckel.

_Polysolenia setosa_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss.
Berlin, p. 299, Taf. viii. fig. 10.

Shell a regular sphere, covered with numerous bristle-shaped radial spines, irregularly scattered between the pores. In the half meridian of the shell two to four very large circular pores (equal to one-third the radius), and between them numerous very small, point-like pores.

_Dimensions._--Diameter of the shell 0.05 to 0.08, of the large pores 0.01, of the small 0.001; length of the spines 0.01 to 0.02.

_Habitat._--West Tropical Pacific, Philippine Sea, Station 206, depth 2100 fathoms.

4. _Acrosphæra spinosa_, Haeckel.

_Collosphæra spinosa_, Haeckel, 1862, Monogr. d. Radiol., p. 536, Taf.
xxxiv. figs. 12, 13.

_Collosphæra spinosa_, Cienkowsky, 1871, Archiv f. mikrosk. Anat., vii.
p. 374, Taf. xxix. figs. 7-17.

Shell a regular or subregular sphere, covered with numerous, obliquely standing spines, irregularly scattered over the surface. In the half meridian of the shell fifteen to twenty irregular {101}roundish pores of very different form and size, one to four times as broad as their bars. Spines conical, irregularly diverging and curved, their hollow base perforated by several pores, not longer than the diameter of the largest pores.

_Dimensions._--Diameter of the shell 0.1 to 0.2, of the pores 0.001 to 0.04; length of the spines 0.01 to 0.02.

_Habitat._--Mediterranean, Messina; Canary Islands, Haeckel.

5. _Acrosphæra collina_, n. sp. (Pl. 8, fig. 2).

Shell quite irregular, polyhedrical, hilly, with a variable number (eight to sixteen) of large conical hill-like prominences; every cone or hill about as high as broad, perforated by the same pores as the shell, on its top bearing a larger irregular roundish pore, and on its edge one single bristle-like spine, not larger than the diameter of this pore, obliquely inserted. In the half meridian of the shell twenty to thirty irregular roundish pores of very different size, one to six times as broad as the bars. A very characteristic species, closely resembling the following _Odontosphæra_.

_Dimensions._--Diameter of the shell 0.15 to 0.25, of the pores 0.005 to 0.02; length of the spines 0.01 to 0.02, height of the hills from which they rise 0.03 to 0.04.

_Habitat._--North coast of New Guinea, Station 218, surface.

6. _Acrosphæra inflata_, n. sp. (Pl. 5, fig. 7).

_Mazosphæra inflata_, Haeckel, 1879, Atlas, _loc. cit._

Shell more or less irregular, polyhedral, hilly, with a variable number (six to twelve) of large pyramidal, hill-like prominences; every hill about as high as broad, on the top a strong conical, radial, or obliquely inserted spine, inflated, with three to six very large polygonal meshes, much larger than the other pores between the hills, which are also polygonal, two to six times as broad as the bars. Ten to fifteen pores on the half meridian.

_Dimensions._--Diameter of the shell 0.1 to 0.14, of the largest pores 0.05, of the smallest 0.005; length of the spines 0.02 to 0.03.

_Habitat._--North Atlantic, Station 64, surface.

Genus 34. _Odontosphæra_,[56] n. gen.

_Definition._--#Collosphærida# with simple shells, the outside of which bears single scattered spines, one single spine on the margin of each larger pore.