Procyttarium, Haeckel, Natürl. Schöpfungsgeschichte, ed. vii. p. 705.
Definition.—Central capsule spherical.
1. Actissa princeps, n. sp. (Pl. 1, fig. 1).
Central capsule spherical, colourless or a little reddish, transparent, with a thick double-edged membrane. Nucleus central, spherical, one-third as broad as the central capsule, containing a single, central, glossy nucleolus. Protoplasm finely granulated, without oil-globules, with numerous clear spherical vacuoles of equal size and at equal distances; the superficial layer of protoplasm (immediately below the membrane) radially striated (fig. 1). In some older specimens the nucleus was divided into numerous small nuclei (fig. 1a), which by further division gave the nuclei of the flagellated spores (fig. 1b); each spore with a very thin lateral flagellum (fig. 1c). Jelly-like calymma twice as broad as the enclosed capsule, without xanthellæ or yellow cells, pierced by innumerable, very thin and long, undivided pseudopodia, which arise from the sarcode-matrix on the outside of the membrane (six to eight times longer than shown in fig. 1).
Dimensions.—Diameter of the central capsule 0.1 to 0.12, of the nucleus 0.03 to 0.04, of the jelly calymma 0.2 to 0.3.
Habitat.—Indian Ocean, Ceylon, Belligemma, Haeckel, 1881; also in a preparation from Station 271, Central Pacific, surface.
2. Actissa primordialis, Haeckel.
Thalassolampe primordialis, R. Hertwig, 1879, Organismus der Radiolarien, p. 32, Taf. iii. fig. 5.
Procyttarium primordiale, Haeckel, 1879, Natürl. Schöpf., ed. vii. p. 705, Taf. xvi. fig. 1.
Central capsule spherical, dim-yellowish, with a thin, simple-edged but compact membrane. Nucleus large, central (about half as broad), with one or two dark nucleoli; on its side an excentric oil-globule, nearly of the same size. Protoplasm between nucleus and membrane, in the younger specimens finely granulated and radially striped; in the older specimens with numerous hyaline globules (vacuoles). Jelly-envelope or calymma very voluminous, ten to twelve times as broad as the central capsule, structureless, containing numerous yellow bodies (xanthellæ?), pierced by very numerous simple pseudopodia.
Dimensions.—Diameter of the central capsule 0.11 to 0.18, of the nucleus 0.04 to 0.09, of the jelly-like calymma 1.2 to 1.5.
Habitat.—Mediterranean, Messina, Hertwig, 1878, surface.
3. Actissa prototypus, n. sp.
Central capsule spherical, red-coloured, with a thick, double-edged membrane. Nucleus central, spherical, half as large as the radius of the capsule, containing a large number (forty to sixty) of small dark nucleoli. Protoplasm filled up with numerous small clear vacuoles, and between them fine red pigment granules; on the inside of the membrane one layer of dark oil-globules. Jelly-like calymma four times as broad as the enclosed capsule, with very numerous small xanthellæ.
Dimensions.—Diameter of the capsule 0.2, of the nucleus 0.05, of the calymma 0.8.
Habitat.—Atlantic, Canary Islands (Lanzerote, Haeckel), 1866; also at Station 348, surface.
4. Actissa radiata, n. sp.
Central capsule spherical, dark, with a thick, double-edged membrane. Nucleus central, spherical, half as large as the capsule, transparent. Protoplasm divided into numerous cuneiform radial pieces which are separated by clear intervals, and filled with very fine dark granules (darker in the distal half). The equatorial optical section exhibits around the circular clear nucleus a coronal of twenty-five such wedge-shaped pieces (mother-cells of spores?) No oil-globules in the central capsule. Jelly-like calymma one and a half times as broad as the enclosed capsule, with numerous small xanthellæ.
Dimensions.—Diameter of the capsule 0.15, of the nucleus 0.07, of the calymma 0.24.
Habitat.—North Pacific, Station 241, surface.
Definition.—Central capsule ellipsoidal, with one prolonged axis.
5. Actissa prunoides, n. sp.
Actiprunum prunoideum, Haeckel, 1882, Manuscript.
Central capsule ellipsoidal, colourless, with a thin, simple-edged membrane. Proportion of its major axis to the minor 4 : 3. Nucleus spherical, its diameter equal to one-third of the minor axis, in its centre a large, dark, spherical nucleolus. Protoplasm clear, containing numerous small vacuoles, separated by regular distances, and on the inside of the capsule-membrane, numerous (forty to fifty) small oil-globules. Calymma (or jelly-veil) ellipsoidal, with a thin sarcode-stratum on the outside of the capsule; its diameter twice as large as that of the central capsule.
Dimensions.—Major axis of the capsule 0.16, minor 0.12; diameter of the nucleus 0.04; major axis of the calymma 0.32, minor 0.24.
Habitat.—Central Pacific, Station 274, surface.
6. Actissa ellipsoides, n. sp.
Actiprunum ellipsoides, Haeckel, 1882, Manuscript.
Central capsule ellipsoidal, red-coloured, with a thick, double-edged membrane. Proportion of its major axis to the minor 5 : 3. Nucleus ellipsoidal, one-third as large as the capsule, containing eight small dark nucleoli. Protoplasm dusky, filled with dark pink pigment-granules; in the major axis, on both poles of the nucleus-axis, two large oil-globules, half as large as the nucleus. Calymma ellipsoidal, with numerous xanthellæ; its diameter four times as large as that of the capsule.
Dimensions.—Major axis of the capsule 0.2, minor 0.12; major axis of the nucleus 0.07, minor 0.04; major axis of the calymma 0.8, minor 0.5.
Habitat.—Mediterranean, Corfu, 1877, Haeckel, surface.
Definition.—Central capsule lenticular, with one shortened axis.
7. Actissa discoides, n. sp.
Actidiscus discoides, Haeckel, 1882, Manuscript.
Central capsule lenticular, red-coloured, about twice as broad as high, with a thick, double-edged membrane. Nucleus spherical, one-third as broad as the capsule, with one single, large central nucleolus. Protoplasm dusky, filled with scarlet pigment; granules and small oil-globules between them. Calymma lenticular, three times as broad as the capsule.
Dimensions.—Major axis of the capsule 0.16, minor 0.08; diameter of the nucleus 0.05; breadth of the calymma 0.5.
Habitat.—North Pacific, Station 236, surface.
8. Actissa lenticularis, n. sp.
Central capsule lenticular, flattened, about three times as broad as high, with a thin, simple-edged membrane. Nucleus lenticular, one-third as large as the capsule, with ten small dark nucleoli. Protoplasm transparent, colourless, filled with small vacuoles at regular distances; on the inside of the membrane in the circular periphery of the lens twenty dark oil-globules. Calymma lenticular, twice as broad as the capsule.
Dimensions.—Major axis of the capsule 0.15, minor 0.05; breadth of the nucleus 0.05, height 0.02; breadth of the calymma 0.03.
Habitat.—East Pacific, Station 272, surface.
9. Actissa phacoides, n. sp.
Actidiscus phacoides, Haeckel, 1882, Manuscript.
Central capsule lenticular, strongly flattened, about four times as broad as high, with a thin, simple-edged membrane. Nucleus lenticular, one-fourth as broad as the capsule, with numerous (twenty or more) small nucleoli. Protoplasm filled with dark pigment-granules; on the inside of the membrane in the circular periphery of the lens thirty-two dark oil-globules. Calymma lenticular, three times as broad as the capsule.
Dimensions.—Major axis of the capsule 0.2, minor 0.05; breadth of the nucleus 0.05, height 0.015; breadth of the calymma 0.6.
Habitat.—Tropical Atlantic, Station 347, surface.
Definition.—Central capsule lentelliptical, with three different axes.
10. Actissa larcoides, n. sp.
Central capsule lentelliptical; with three different axes, bearing the proportion 4 : 3 : 2. Nucleus spherical; its diameter equal to the shortest radius of the capsule. No nucleoli visible. Protoplasm transparent, with small vacuoles; on the inside of the thin capsule-membrane numerous (fifty to sixty) small oil-globules, regularly disposed. Calymma lentelliptical, twice as large as the central capsule.
Dimensions.—Major axis or length of the capsule 0.2, middle axis or breadth 0.15, minor axis or height 0.1; diameter of the nucleus 0.05, of the calymma 0.3-0.4.
Habitat.—Central Pacific, Station 266, surface.
Definition.—Thalassicollida without extracapsular alveoles, but with large roundish or globular alveoles within the central capsule, with a simple spherical, not branched nucleus in the centre.
The genus Thalassolampe is, next to Actissa, the most simple of all Radiolaria, but differs from it by the large intracapsular alveoles. By these the central capsule is inflated to an extraordinary size, which in Thalassolampe maxima exceeds that of most other Radiolaria. From the nearly allied Thalassopila it differs by the simple spherical nucleus, from Physematium by the absence of spicula. Of the two species of the genus the first observed Thalassolampe margarodes, 1862, is Mediterranean, the second, Thalassolampe maxima, 1882, is Indian.
1. Thalassolampe margarodes, Haeckel.
Thalassolampe margarodes, Haeckel, 1862, Monogr. d. Radiol., p. 253, Taf. ii. figs. 4, 5.
Thalassolampe margarodes, R. Hertwig, 1876, Histologie d. Radiol., p. 68, Taf. iii. figs. 1-5.
Spherical body very soft and limpid, somewhat pearl-like opalescent, yellowish or bluish. Central capsule with a very thin structureless membrane, its diameter six to eight times as large as that of the central spherical nucleus. Wall of the vesicular nucleus thick, perforated by fine pore-canals; on its inside often numerous oval nucleoli. In the movable protoplasmic network between the large alveoles a considerable number of large yellowish or orange oil-globules. Extracapsular jelly-envelope very thin, contains small yellow bodies (zooxanthellæ). (Compare the accurate description of this Mediterranean species in my monograph and in Hertwig's work.) In the Canary Islands I found very often a large variety of it, of double and triple the size, distinguished by the delicate orange colour of the intracapsular oil-globules. This may be distinguished as Thalassolampe aurantiaca.
Dimensions.—Diameter of the whole jelly-sphere 2 to 4 mm., of the central capsule 2 to 3 mm., of its nucleus 0.2 to 0.4 mm.
Habitat.—Mediterranean, Messina, Haeckel, Hertwig; Canary Islands, Lanzerote, Haeckel; surface.
2. Thalassolampe maxima, n. sp. (Pl. 1, fig. 2).
Spherical body quite pellucid, like a glass globule, colourless. Central capsule with a moderately thick, but quite transparent, structureless membrane, its diameter ten to twelve times as large as that of the central spherical nucleus. Wall of the vesicular nucleus thick, perforated by fine pore-canals; on its inside numerous small spherical nucleoli. No large oil-globules in the movable protoplasmic network between the large alveoles. Extracapsular jelly-envelope very thin, containing no yellow bodies. This differs from the preceding nearly allied species in the want of the intracapsular oil-globules and of the extracapsular yellow bodies. It possesses the largest central capsule of all known Radiolaria. I found them living and floating in water taken from the surface of the Indian Ocean by a bucket.
Dimensions.—Diameter of the whole jelly-body 12 to 15 mm., of the central capsule 10 to 12 mm., of the nucleus 0.8 to 1.2 mm.
Habitat.—Indian Ocean, near the Maldive Islands, Haeckel, 1882, surface.
Definition.—Thalassicollida without extracapsular alveoles, but with large roundish or globular alveoles within the central capsule, with a papillate or branched nucleus in its centre.
The genus Thalassopila has, like Thalassolampe, a voluminous foamy central capsule, inflated by numerous large alveoles; but it differs in the complicated form of the nucleus, which is like that of Thalassophysa, and is either branched or occupied by conical or roundish papillæ.
1. Thalassopila cladococcus, n. sp. (Pl. 1, fig. 3).
Spherical body dark-spotted, with a thin yellowish jelly-envelope. Central capsule with a thick and firm membrane, perforated by pores; its diameter three times that of the central nucleus, three-fourths that of the whole jelly-sphere. Nucleus profusely branched or papillated, its spherical surface covered with numerous (more than a hundred) finger-shaped obtuse blind sacs, about as long as its radius. Protoplasm of the central capsule forming a loose network between the large roundish alveoles, in the cortical zone radially striped and containing one layer of large dark oil-globules. These are regularly distributed on the inside of the capsule-membrane and separated by intervals, twice as broad as its diameter, giving to the capsule-surface a spotted appearance. Extracapsular jelly-envelope thin, yellowish, with very numerous and small xanthellæ.
Dimensions.—Diameter of the whole jelly-sphere 5 mm., of the central capsule 4 mm., of the nucleus 1.3 mm.
Habitat.—Antarctic Ocean, Station 154 (south of Kerguelen), surface.
Definition.—Thalassicollida without intracapsular alveoles, but with large roundish or globular alveoles within the extracapsular calymma. Nucleus in the centre of the capsule simple spherical, not branched.
The genus Thalassicolla was proposed by Huxley in 1851, for a certain number of different voluminous jelly-like Radiolaria, which he had observed living during his voyage in the "Rattlesnake" through the tropical seas, and of which he gives an excellent description—the first accurate observations on living Radiolaria. Johannes Müller afterwards removed from this genus the social genera Sphærozoum and Collosphæra (formerly Thalassicolla punctata), and retained as type of the genus Thalassicolla nucleata. In 1862 in my Monograph I added two other species, Thalassicolla pelagica and Thalassicolla zanclea, and later (1870) Thalassicolla sanguinolenta. Now I think it better to separate the last two species as a new genus, Thalassophysa, characterised by the papillate or branched nucleus, and to retain in Thalassicolla only those forms with simple spherical nucleus. For both genera the extracapsular, voluminous, spherical calymma or jelly-envelope, with numerous large alveoles, is characteristic. The membrane of the central capsule in Thalassicolla is now structureless (subgenus Thalassicollarium, with three species), now characterised by a peculiar structure, prominent ridges on the inside of the membrane, which form a network with polygonal plates, resembling an epithelium (Pl. 1, fig. 5b; subgenus Thalassicollidium, with four species). Of the seven species here described, two are cosmopolitan, widely distributed, and common; one is Mediterranean, one Atlantic, and three Pacific.
Definition.—Membrane of the central capsule structureless, only perforated by innumerable very small radial pores.
1. Thalassicolla pellucida, n. sp.
Spherical body very soft, transparent, clear and colourless, without any pigment. Central capsule soft, hyaline, with a thin, structureless, not areolated membrane. Diameter of the central capsule about three times that of the nucleus, one-fourth to one-sixth that of the jelly-envelope. Nucleus delicate, transparent, with one single central nucleolus, about one-third its diameter. Protoplasm of the central capsule contains only small, pellucid, densely packed globules (vacuoles?), no oil-globules. Extracapsular body quite transparent, without pigment or oil-globules, only composed of the large alveoles imbedded in the jelly-cover, and of the fine protoplasmic network between them. No xanthellæ.
Dimensions.—Diameter of the central capsule 0.8 to 1.2, of the nucleus 0.3 to 0.4, of the calymma 3 to 6 mm.
Habitat.—Cosmopolitan, Canary Islands, Haeckel; Cape, Australia, Pacific, Challenger; surface.
2. Thalassicolla spumida, n. sp.
Spherical body nearly transparent, yellowish, without dark pigment. Central capsule pellucid, with a thick, structureless, not areolated membrane. Diameter of the central capsule about twice that of the nucleus, one-sixth to one-eighth that of the jelly-cover. Nucleus delicate, somewhat opaque, with numerous small nucleoli. Protoplasm of the central capsule contains small pellucid globules (vacuoles?), and immediately under its membrane (on its inside) one single layer of large, dark, refractive oil-globules. Extracapsular body very voluminous, foamy, with innumerable alveoles in the jelly, and many xanthellæ between them.
Dimensions.—Diameter of the central capsule 0.6 to 0.8, of the nucleus 0.3 to 0.4, of the calymma 3 to 5 mm.
Habitat.—Atlantic, Canary Islands, Haeckel; Cape Verde Islands, Challenger Station 350; Brazil, Rabbe; surface.
3. Thalassicolla zanclea, Haeckel.
Thalassicolla zanclea, Haeckel, 1862, Monogr. d. Radiol., p. 252, Taf. ii. fig. 3.
Spherical body opaque, transparent only in the periphery, with colourless central capsule, but with brown or black pigment-powder scattered everywhere through the extracapsular alveolated jelly-cover. Central capsule soft, transparent, colourless, with a thin structureless, not areolated membrane. Diameter of the central capsule about one and a half times that of the nucleus, one-half or one-third that of the jelly-cover. Nucleus delicate, transparent, with a thin, finely punctated membrane, with one or more nucleoli. Protoplasm of the central capsule contains only small, pellucid, densely packed globules (vacuoles?), no oil-globules. Extracapsular body very dark and opaque, with a great mass of brown or blackish-brown pigment between the alveoles of the jelly-cover. Numerous xanthellæ.
Dimensions.—Diameter of the central capsule 0.1 to 0.12, of the nucleus 0.07 to 0.08, of the calymma 0.2 to 0.4.
Habitat.—Mediterranean, Messina, Haeckel.
Definition.—Membrane of the central capsule areolated, with small polygonal plates, resembling an epithelial cell-tissue, spotted by innumerable fine radial pores.
4. Thalassicolla australis, n. sp.
Spherical body nearly transparent, without dark pigment. Central capsule colourless, somewhat opaque, with a thick and firm, very elastic membrane, areolated by polygonal, punctated figures resembling cells. Diameter of the central capsule about three times that of the nucleus, one-third that of the jelly-cover. Nucleus thin-walled, with many small nucleoli. Protoplasm of the central capsule finely granulated, containing numerous hyaline globules (vacuoles?) of different size, and in each of these one single roundish, dark refringing corpuscle, concentrically lamellated like an amylum grain. Extracapsular body without pigment or oil-globules, only composed of the large alveoles imbedded in the jelly-cover, and of the fine protoplasmic network between them. No xanthellæ.
Dimensions.—Diameter of the central capsule 1 to 2, of its nucleus 0.3 to 0.4, of the nucleoli 0.12 to 0.16, of the hyaline globules in the protoplasm of the capsule 0.02 to 0.05; calymma, 4 to 6 mm.
Habitat.—South-west Pacific, east coast of Australia, New Zealand, &c.; Challenger Stations 163, 171; surface.
5. Thalassicolla nucleata, Huxley.
Thalassicolla nucleata, Huxley, 1851, Ann. and Mag. Nat. Hist., ser. 2, vol. viii. p. 435, pl. xvi. fig. 4.
Thalassicolla nucleata, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 28.
Thalassicolla coerulea, Schneider, 1858, Archiv f. Anat. u. Physiol., p. 40, Taf. iii. Bd. i. figs. 5-7.
Thalassicolla nucleata, Haeckel, 1862, Monogr. d. Radiol., p. 249, Taf. iii. figs. 1-5.
Thalassicolla nucleata, R. Hertwig, 1876, Histologie d. Radiol., p. 43, Taf. iii. figs. 61-5, Taf. iv., v.
Thalassicolla nucleata, R. Hertwig, 1879, Organismus d. Radiol., p. 34.
Spherical body in the central part opaque, black or dark coloured, in the periphery transparent, whitish, or yellowish. Central capsule rather compact, yellowish, opaque, with a thick and firm, very elastic membrane, areolated by polygonal, punctated figures resembling cells. Diameter of the central capsule about twice as large as that of the nucleus, one-half to one-fourth that of the jelly-cover. Nucleus with a very thick, finely punctated membrane, containing a viscous fluid (when coagulated finely granular), and sometimes one large, central, spherical, or ramified nucleolus, sometimes a variable number of smaller roundish nucleoli. Protoplasm of the central capsule containing many very variable corpuscles, mostly pellucid (albuminous?) spherules, containing oil-globules, or concentric amyloid concretions, or crystals, &c. Extracapsular body with dark pigment-powder of variable colour (black, brown, violet, blue, &c.), densely aggregated around the central capsule, more loosely dissipated between the alveoles of the outer jelly-cover. Xanthellæ very numerous.
Dimensions.—Diameter of the central capsule 0.4 to 0.8, of the nucleus 0.02 to 0.05, of the calymma 1 to 5 mm.
Habitat.—Cosmopolitan; common in all warmer seas; Mediterranean, Atlantic, Indian Ocean, Pacific, mainly between lat. 40° N. and lat. 40° S.; surface.
6. Thalassicolla maculata, n. sp. (Pl. 1, fig. 4).
Spherical body in the central part opaque, black or dark coloured, in the periphery semi-transparent, spotted. Central capsule compact, yellowish, opaque, with a thick and firm, very elastic membrane, areolated by polygonal, punctated figures resembling cells. Diameter of the central capsule about twice that of the nucleus, one-third to one-fifth that of the jelly-cover. Nucleus thin-walled, with one large spherical nucleolus. Protoplasm of the central capsule contains innumerable very small, hyaline, spherical vesicles of equal size (or vacuoles?), two to four times as broad as the separating bridges of protoplasm. Extracapsular body with dark pigment-powder of black or brown colour, densely accumulated around the central capsule (in the matrix), loosely scattered between the alveoles of the outer jelly-cover. The latter appears spotted by numerous large, roundish lumps of protoplasm, scattered between the alveoles. No xanthellæ.
Dimensions.—Diameter of the central capsule 0.3 to 0.6, of the nucleus 0.2 to 0.3, of the hyaline globules in the protoplasm of the capsule 0.02 to 0.03; calymma, 2 to 3 mm.
Habitat.—South Pacific, Challenger Station 289.
7. Thalassicolla melacapsa, n. sp. (Pl. 1, fig. 5).
Spherical body in the central part opaque, black or dark coloured, in the periphery semi-transparent, spotted. Central capsule compact, black, with a thick and firm, very elastic membrane, areolated by polygonal, punctated figures resembling cells. Diameter of the central capsule about twice that of the nucleus, one-third or half that of the jelly-cover. Nucleus thin-walled, transparent, containing very numerous and small nucleoli. Protoplasm of the central capsule filled with small black pigment-granules, quite intransparent, contains densely packed hyaline (albuminous?) globules of equal size; every pellucid globule includes a smaller globule (one-third or one-fourth its diameter), which appears to be composed of aggregated oil-bubbles. Extracapsular body without pigment, contains between its alveoles in the inner half numerous, dark refractive oil-globules, in the outer half numerous amœboid lumps of protoplasm, irregularly scattered. No xanthellæ.
Dimensions.—Diameter of the central capsule 2 to 2.5, of the nucleus 1 to 1.5, of the hyaline globules in the protoplasm of the capsule 0.03 to 0.04; calymma, 3 to 5 mm.
Habitat.—South-east Pacific (near Valparaiso), Challenger Station 300, surface.
Definition.—Thalassicollida without intracapsular alveoles, but with large roundish or globular alveoles within the extracapsular calymma. Nucleus in the centre of the capsule papillate or branched.
The genus Thalassophysa contains those species of Thalassicollida formerly associated with Thalassicolla, which are distinguished by the complicated, ramose, or papillate form of the large nucleus. All three species here described are found in the Mediterranean and the Atlantic. To this genus appertains also that strange form of Radiolaria which I described in 1870 as Myxobrachia (compare Thalassophysa sanguinolenta).
1. Thalassophysa papillosa, n. sp.
Thalassicolla papillosa, Haeckel, 1867, Manuscript.
Spherical body transparent, colourless, or somewhat yellowish. Central capsule soft, colourless, with a very thin but firm, elastic, structureless membrane. Diameter of the central capsule about twice that of the nucleus, one-fourth to one-sixth that of the jelly-envelope. Nucleus papillated, its spherical surface covered with a great number (50 to 80) of conical or finger-like protuberances or blind sacs, not longer than half its radius. Protoplasm of the central capsule filled with very small and numerous spherical vacuoles, without oil-globules. Extracapsular jelly-body, without dark pigment, oil-globules, and large protoplasmic lumps, contains between its alveoles very numerous xanthellæ.
Dimensions.—Diameter of the whole jelly sphere 4 to 5 mm., of the central capsule 0.8 to 1 mm., of its nucleus 0.4 to 0.5.
Habitat.—Canary Islands, Lanzerote, common, Haeckel; Cape Verde Islands, Challenger; surface.
2. Thalassophysa sanguinolenta, Haeckel.
Thalassicolla sanguinolenta, Haeckel, 1870, Jenaische Zeitschr., Bd. v. p. 526, Taf. 18.
Thalassicolla sanguinolenta, Haeckel, 1870, Biolog. Studien, i. p. 113, Taf. iv.
Thalassicolla sanguinolenta, R. Hertwig, 1879, Organismus d. Radiol., p. 37, Taf. iii. fig. 1.
Myxobrachia rhopalum, Haeckel, 1870, Jenaische Zeitschr., Bd. v. p. 519, Taf. 18 (et in Biol. Stud., loc. cit.).
Myxobrachia pluteus, Haeckel, 1870, Jenaische Zeitschr., Bd. v. p. 520, Taf. 18 (et in Biol. Stud., loc. cit.).
Spherical body in the central part opaque, reddish, in the periphery transparent, yellowish. Central capsule compact, white, red spotted, with a thick elastic membrane, perforated by pores, but not areolated. Diameter of the central capsule three times that of the nucleus, one-fifth to one-eighth that of the jelly-envelope. Nucleus papillated, its spherical surface covered with numerous (80 to 120) conical or finger-like protuberances not longer than one-fourth or one-third of its radius. On the inside of these blind sacs lie numerous small roundish nucleoli. Protoplasm of the central capsule in the outer (cortical) zone (on the inside of the membrane) radially striped, with one layer of very numerous red oil-globules of equal size, producing its blood-spotted appearance; in the inner (medullary) zone foamy, with numerous small spherical vacuoles. Extracapsular jelly-body without dark pigment, contains between its alveoles no large protoplasmic lumps (as in Thalassophysa pelagica), but numerous small oil-globules and xanthellæ. This species sometimes amasses in its jelly-envelope large accumulations of Coccoliths and Coccospheres, which are much heavier than the jelly-body, and produce arm-like protuberances of it; this modified form, often of very regular and peculiar appearance, I formerly described as Myxobrachia (compare my Biolog. Studien, loc. cit., and Hertwig, loc. cit., p. 37). Compare also Myxobrachia cienkowski, Wagner, 1872, L. N. 23.
Dimensions.—Diameter of the whole jelly-sphere 5 to 8 mm., of the central capsule 1 to 1.2 mm., of its nucleus 0.3 to 0.4.
Habitat.—Canary Islands, Lanzerote; common, Haeckel; Mediterranean, Messina, Hertwig; surface.
3. Thalassophysa pelagica, Haeckel.
Thalassicolla pelagica, Haeckel, 1862, Monogr. d. Radiol., p. 247, Taf. i.
Thalassicolla pelagica, R. Hertwig, 1879, Organismus d. Radiol., p. 35, Taf. iii. fig. 4.
Spherical body in the central part opaque, yellowish, in the periphery semi-transparent, spotted. Central capsule compact, yellowish-white, with a thick and compact membrane, perforated by pores, but not areolated. Diameter of the central capsule about twice that of the nucleus, one-half to one-sixth that of the jelly-envelope. Nucleus papillated, its spherical surface covered with numerous (20 to 60) conical, roundish, or finger-like protuberances, not longer than its radius (commonly only one-half or one-third as long). Enclosed in the semi-fluid substance of the nucleus are very long and thin cylindrical nucleoli snake-like, contorted, and penetrating into the protuberances of the nucleus. Protoplasm of the central capsule in the outer (cortical) zone (on the inside of the membrane) radially striped, with one layer of large oil-globules of different sizes; in the inner (medullary) zone foamy, with numerous small spherical vacuoles, mostly of equal size. Extracapsular jelly-body without dark pigment, contains between its alveoles a large number of large roundish or amœboid lumps of protoplasm, and very numerous yellow cells or xanthellæ (compare the detailed description in my Monograph, and in R. Hertwig's work).
Dimensions.—Diameter of the whole jelly-sphere 1 to 4 mm., of the central capsule 0.5 to 0.6, of the nucleus 0.2 to 0.3.
Habitat.—Mediterranean—Messina, Corfu, Nizza, Genoa, Haeckel; Messina, R. Hertwig; surface.
Collozoida, Haeckel, 1862, Monogr. d. Radiol., p. 522.
Definition.—Colloidea socialia.
The family Collozoida comprises all associated or colony-building Radiolaria without skeleton. We unite here all these skeletonless Radiolarian colonies into one single genus Collozoum, constituted (1862) in my Monograph (p. 522). The oldest known form of it was the Collozoum inerme, described firstly by Johannes Müller (1856) as Sphærozoum inerme. Two other species of the genus were figured (1862) in my Monograph (p. 522, Tafn. xxxii., xxxv.). A most accurate description of its histological structure and development was given in 1876 by Richard Hertwig in his Histologie der Radiolarien (pp. 12-42, Tafn. i., ii.). A number of other very remarkable forms of Collozoum have been observed by me during the last few years, and partly figured in Pl. 3.
Collozoum, as the only representative of this family, is sufficiently distinguished from all other Radiolaria by the definition "Skeletonless Radiolarian Colonies." These occur floating on the surface of all warmer seas, often in astonishing masses, and may be easily confounded, owing to their external resemblance, with the jelly-like egg-masses of certain Mollusca. Collozoum is derived either from Actissa or from Thalassicolla, simply by multiplication of the unicellular body and by reunion of the associated capsules in one common calymma or jelly-veil; this is constantly alveolated, as in Thalassicolla. As in Actissa, the form of the central capsule remains either spherical, or it becomes ellipsoidal or discoidal, rarely polyhedral or amœboid. In Collozoum as in all colonial Radiolaria, the original central nucleus commonly undergoes cleavage very early into numerous small nuclei, whilst its place is usually taken by a central oil-globule. This peculiarity may serve often (but not constantly) for the distinction of isolated capsules of Collozoum from Actissa.
Definition.—Skeletonless colonies of Radiolaria.
The genus Collozoum, as already mentioned, is the only representative of its family, and comprises all Radiolaria living associated in colonies, and having no skeleton. Therefore Collozoum possesses all the peculiarities described above. Although the floating colonies of this genus occur in enormous masses on the surface of all warmer seas, nevertheless the number of different species in this genus is not great, and amounts only to thirteen. If this number increase by further investigations, the subgenera distinguished in the following description can be advanced to the range of genera; in which case Collodinium (or Collozoum sensu restricto) will be characterised by the spherical form of its central capsules, Colloprunum by the ellipsoidal form (Pl. 3, fig. 9), Collophidium by the cylindrical, very prolonged form (figs. 2, 3), Collodiscus by the lenticular or discoidal form, and Collodastrum by the indefinite, polyhedral, or amœboid form (figs. 4, 5).
Definition.—Form of the central capsules spherical or subspherical, never polyhedral, ellipsoidal, or cylindrical.
1. Collozoum inerme, Haeckel (Pl. 3, figs. 10-12).
Collozoum inerme, Haeckel, 1862, Monogr. d. Radiol., p. 522, Taf. xxxv.
Collozoum inerme, Cienkowski, 1871, Archiv. f. mikrosk. Anat., vol. vii. p. 376, Taf. xxix. figs. 18-36.
Collozoum inerme, R. Hertwig, 1876, Histologie der Radiol., p. 12, Taf. i., ii.
Collozoum inerme, R. Hertwig, 1879, Organismus d. Radiol., p. 31, Taf. iii. fig. 12.
Sphærozoum inerme, J. Müller, 1856, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 478; Abhandl., p. 54.
Sphærozoum bicellulare, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 54, Taf. viii. fig. 5.
Thalassicolla punctata, Huxley (pro parte), 1851, Ann. and Mag. Nat. Hist., ser. 2, vol. viii. p. 433.
Central capsules spherical, with thin, simple-edged membrane, with one single oil-globule in the centre. (If the capsules multiply by division, the spherical form becomes violin-shaped, constricted in the middle; and in this condition the number of oil-globules increases; but in the ordinary mature state the capsule of this species remains spherical, and its oil-globule solitary. In quite young capsules the oil-globules are wanting; Pl. 3, fig. 12.)
Dimensions.—Diameter of the central capsules 0.04 to 0.16.
Habitat.—Cosmopolitan, common in all warmer seas (Mediterranean, Atlantic, Indian, and Pacific), surface.
2. Collozoum nostochinum, n. sp.
Central capsules spherical, very large, opaque, distended with red pigment-granules and with very numerous (two hundred to three hundred) small oil-globules. Membrane thick, double-edged.
Dimensions.—Diameter of the central capsules 0.3 to 0.5.
Habitat.—Indian Ocean, off Socotra, surface, Haeckel.
3. Collozoum volvocinum, n. sp.
Central capsules spherical, very large, opaque, containing a great number (ten to thirty) of large oil-globules, and between them densely packed masses of dark pigment. Membrane thick, double-edged. This species differs from Collozoum inerme, mainly by the great size of the central capsules (three to five times as big as in the former) and the great number of oil-globules in them.
Dimensions.—Diameter of the central capsules 0.2 to 0.3.
Habitat.—Central Pacific, Station 272, surface.
Definition.—Form of the central capsules ellipsoidal, with one prolonged axis.
4. Collozoum ovatum, n. sp.
Colloprunum ovatum, Haeckel, 1882, Manuscript.
Central capsules ovate or ellipsoidal, its longer diameter twice to three times as large as the shorter. In the centre of every capsule one single oil-globule.
Dimensions.—Length of the central capsules 0.2 to 0.3, breadth of them 0.1 to 15.
Habitat.—North Pacific, Station 244, surface.
5. Collozoum ellipsoides, n. sp. (Pl. 3, figs. 8, 9).
Colloprunum ellipsoides, Haeckel, 1882, Manuscript.
Central capsules regularly ellipsoidal, very large; their longer diameter once and a half to twice as large as the shorter. In every capsule fifty to eighty oil-globules.
Dimensions.—Length of the central capsules 0.3 to 4, breadth of them 0.2.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), surface, John Murray.
Definition.—Form of the central capsules cylindrical, often snake-like, contorted, with one axis much prolonged, several times longer than the transverse axis.
6. Collozoum contortum, n. sp.
Collophidium contortum, Haeckel, 1882, Manuscript.
Central capsules cylindrical, three to four times as long as broad, C- or S-like curved, transparent, without oil-globules.
Dimensions.—Length of the central capsules 0.2 to 0.3, breadth 0.06 to 0.08.
Habitat.—Tropical Atlantic, Station 347, surface.
7. Collozoum serpentinum, n. sp. (Pl. 3, figs. 1-3).