. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 189 Order 3.—RADIOLARIA.* Jfarine Rhizopoda with complicated differentiation of the sarcode body, loith central capsule and radial silicious skeleton. The sarcode body contains a membranous porous capsule (the central capsule), in which is contained a tough slimy protoplasm with vacuoles and granules (intracapsular sarcode), fat and oil globules, and albuminous bodies, and more rarely crystals and con- cretions. The intracapsular mass contains also a single large nucleus or sev
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 189 Order 3.—RADIOLARIA.* Jfarine Rhizopoda with complicated differentiation of the sarcode body, loith central capsule and radial silicious skeleton. The sarcode body contains a membranous porous capsule (the central capsule), in which is contained a tough slimy protoplasm with vacuoles and granules (intracapsular sarcode), fat and oil globules, and albuminous bodies, and more rarely crystals and con- cretions. The intracapsular mass contains also a single large nucleus or several small nuclei. The sarcode which surrounds the capsule and which emits on all sides simple or anastomosing pseudopodia, contains numerous yellow cells, sometimes pigment masses; and in some cases delicate trans- parent vesicles, or alveoli, are found in the peripheral layer between the radia- ting pseudopodia (Thalas- sicolla pelagica, fig. 129). Many Radio! aria form colonies, and are composed of numerous individual?. [n such colonies the al- veoli are placed in the common protoplasm, which contains in itself, not as in the monozoic Radiolaria a single cen- tral capsule, but a number of capsules. Only a few species remain naked and without firm deposits; as a rule, the soft body possesses a silicious skeleton, which either lies entirely outside the central capsule (Ectolithia) or is partially within it (Entolithia). In the most simple cases the skeleton consists of tanall, simple, or toothed silicious needles (spicula) united together, which sometimes give rise to a fine sponge work round the periphery of the proto- plasm, , Physematium. In a higher grade we find stronger hollow silicious spicules, which radiate from the middle point of the body to the periphery in regular number and order, , Acanthometra * Job. Miiller, " Ueber die Thalassicollen, Polycystinen und Acanthomctrcn," Abh. tier Bcrl. ATtad. 1858. E. Haeckel,il Die Radiolarien," Eine M
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