Family II. Collozoida, Haeckel, 1862 (Pl. )

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. .

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.

Genus 6. Collozoum, Haeckel, 1862, Monogr. d. Radiol., p. 522.

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. , 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).

Subgenus 1. Collodinium, Haeckel.

Definition.—Form of the central capsules spherical or subspherical, never polyhedral, ellipsoidal, or cylindrical.

1. Collozoum inerme, Haeckel (Pl. , 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. , 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.

Subgenus 2. Colloprunum, Haeckel.

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. , 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.

Subgenus 3. Collophidium, Haeckel.

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. , figs. 1-3).

Collophidium serpentinum, Haeckel, 1882, Manuscript.

Central capsules cylindrical, filiform, much elongated, ten to one hundred times, sometimes two hundred to four hundred times as long as broad, snake-shaped or worm-shaped, curved and contorted in the most irregular manner, often spiral or twisted into a large nodule. Numerous oil-vesicles constantly present, forming one series of globules in the axis of every capsule; distance of the globules, one from another, and also from the capsule-membrane, about equal to their diameter. (This interesting and very curious form was very frequently observed living by me in the Canary Islands, in January 1867; the jelly-colonies were commonly spherical, and contained fifty to two hundred or more capsules of very different size and form.)

Dimensions.—Length of the central capsules 1 to 10, sometimes 20 to 40 mm.; average breadth 0.1 mm.

Habitat.—Canary Islands, Lanzerote, Haeckel, surface.

8. Collozoum vermiforme, n. sp. (Pl. , figs. 6, 7).

Collophidium vermiforme, Haeckel, 1882, Manuscript.

Central capsules cylindrical, much elongated, five to ten times (sometimes twenty to fifty times) as long as broad, snake-shaped or worm-shaped, very irregularly curved and contorted. Numerous oil-globules constantly present, forming in the axis of every capsule a double series of alternating rose-coloured globules. (This species is nearly allied to the preceding; but its capsules are thicker and shorter, and the oil-vesicles in them are arranged not in a single, but in a double row.)

Dimensions.—Length of the central capsules 0.6 to 1.2 mm., sometimes 3 to 6 mm.; breadth 0.12.

Habitat.—Tropical Atlantic, near the west coast of Africa, Station 349, Canary Islands, surface.

Subgenus 4. Collodiscus, Haeckel.

Definition.—Form of the central capsules discoidal or lenticular, with one shortened axis.

9. Collozoum coeruleum, Haeckel.

Collozoum coeruleum, Haeckel, 1862, Monogr. d. Radiol., p. 523, Taf. xxxii. figs. 6-8.

Collodiscus coeruleus, Haeckel, 1882, Manuscript.

Central capsule lenticular or discoidal, flattened, blue coloured, with one single oil-globule in the centre. Protoplasm containing numerous crystals and dark blue pigment-granules. Membrane very thick, double-edged. (Whilst at Messina in 1859 I found this form not constantly discoidal, in 1867 in the Canary Islands I observed it constantly lenticular.)

Dimensions.—Breadth of the central capsules 0.1 to 0.15, height 0.04 to 0.08.

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

10. Collozoum discoideum, n. sp.

Collodiscus discoideus, Haeckel, 1882, Manuscript.

Central capsule discoidal, flattened, transparent, with a ring of twenty to twenty-five oil-globules in its circular periphery (on the inside of the thin membrane).

Dimensions.—Breadth of the central capsules 0.2, height 0.05.

Habitat.—South Pacific (Juan Fernandez), Station 300, surface.

Subgenus 5. Collodastrum, Haeckel.

Definition.—Form of the central capsules irregular and indefinite, variable, commonly polyhedral or polygonal, or amœboid, often with irregular, finger-like processes.

11. Collozoum pelagicum, Haeckel.

Collozoum pelagicum, Haeckel, 1862, Monogr. d. Radiol., p. 525, Taf. xxxii. figs. 4, 5.

Sphærozoum pelagicum, Haeckel, 1860, Monatsber. d. k. Akad. d. Wiss. Berlin, 1860, p. 845.

Central capsules small, quite irregularly formed, roundish-polyhedral or depressed-polygonal, transparent, without oil-globules. Often many extracapsular oil-vesicles in the common jelly-body between the central capsules. Membrane very thin and delicate.

Dimensions.—Diameter of the central capsules 0.02 to 0.08.

Habitat.—Mediterranean, Messina, Haeckel; Naples, Brandt; surface.

12. Collozoum stellatum, n. sp.

Collodastrum stellatum, Haeckel, 1882, Manuscript.

Central capsules star-shaped, irregularly radiating, with a great number (eight to twenty or more) of radial, short, conical, acute processes, very variable in size and number. Membrane thin. In every capsule several (four to eight) oil-globules.

Dimensions.—Diameter of the central capsules 0.12 to 0.2.

Habitat.—Central Pacific, Station 274, surface.

13. Collozoum amœboides, n. sp. (Pl. , figs. 4, 5).

Collodastrum amœboides, Haeckel, 1882, Manuscript.

Central capsules amœbiform, of moderate size, quite irregularly formed, with a variable number of finger-like, obtuse, irregular prolongations (commonly three to six), very variable in size and form. Membrane thin. In the centre of every capsule one single oil-globule.

Dimensions.—Diameter of the central capsules 0.04 to 0.08.

Habitat.—Indian Ocean, Ceylon, Haeckel; Madagascar, Rabbe; surface.