File:EB1911 Radiolaria (1).jpg

English: Radiolaria: 1. Central capsule of Thalassicolla nucleata, Huxley, in radial section. a, the large nucleus (Binnenbläschen); b, corpuscular structures of the intracapsular protoplasm containing concretions; c, wall of the capsule (membranous shell), showing the fine radial pore-canals; d, nucleolar fibres (chromatin substance) of the nucleus. 2, 3. Collozoum inerme, J. Müller, two different forms of colonies, of the natural size. 4. Central capsule from a colony of Collozoum inerme, showing the intracapsular protoplasm and nucleus, broken up into a number of spores, the germs of swarm-spores or flagellulae; each encloses a crystalline rod. c, yellow cells lying in the extracapsular protoplasm. 5. A small colony of Collozoum inerme, magnified 25 diameters. a, alveoli (vacuoles) of the extracapsular protoplasm; b, central capsules, each containing besides protoplasm a large oil-globule. 6-13. Yellow cells of various Radiolaria: 6, normal yellow cell; 7. 8, division with formation of transverse septum; 9, a modified condition according to Brandt; 10, division of a yellow cell into four; 11, amoeboid condition of a yellow cell from the body of a dead Sphaerozoon; 12, a similar cell in process of division; 13, a yellow cell the protoplasm of which is creeping out of its cellulose envelope. 14. Heliosphaera inermis, Haeck., living example; a, nucleus; b, central capsule; c, siliceous basket-work skeleton. 15. Two swarm-spores (flagellulae) of Collozoum inerme, set free from such a central capsule as that drawn in 4; each contains a crystal b and a nucleus a. 16. Two swarm-spores of Collozoum inerme, of the second kind, viz. devoid of crystals, and of two sizes, a macrospore and a microspore. They have been set free from central capsules with contents of a different appearance from that drawn in 4. a, nucleus. 17. Actinomma asterocanthion, Haeck.; one of the Peripylaea. Entire animal in optical section. a, nucleus; b, wall of the central capsule; c, innermost siliceous shell enclosed in the nucleus; c¹, middle shell lying within the central capsule; c², outer shell lying in the extracapsular protoplasm. Four radial siliceous spines holding the three spherical shells together are seen. The radial fibrillation of the protoplasm and the fine extracapsular pseudopodia are to be noted. 18. Amphilonche messanensis, Haeck.; one of the Acanthometridea. Entire animal as seen living.