The inception and digestion of nutriment, as it usually appears to take place by the pseudopodia, has already been so fully treated in my Monograph (L. N. 16, pp. 135-140), and since then in my paper on the sarcode body of the Rhizopoda (L. N. 19, p. 342), that I have nothing of importance to add. Quite recently Karl Brandt has expressed a doubt as to whether the taking up of formed particles by the pseudopodia and their aggregation in the calymma be really connected with the process of nutrition. He is disposed rather to believe that these foreign bodies are usually only accidentally and mechanically brought into the calymma, and that the nourishment of the Radiolaria is derived exclusively or pre-eminently from the symbiotic Xanthellæ (L. N. 52, pp. 88-93). I must, however, maintain my former opinion, which I have only modified insomuch that I now regard the sarcodictyum (on the outer surface of the calymma, § 94) rather than the sarcomatrix (on the outer surface of the central capsule, § 92) as the principal seat of true digestion and assimilation. From the sarcodictyum the dissolved and assimilated nutritive matters may pass by the intracalymmar pseudopodia (or sarcoplegma, § 93) into the sarcomatrix, and hence may reach the endoplasm through the openings in the central capsule. To what an extent the Radiolaria are capable of taking up even large formed bodies into the calymma, is shown by the {cxxxi}striking instance of _Thalassicolla sanguinolenta_, which becomes so deformed by the inception of numerous coccospheres and coccoliths, that I described it as a special genus under the name _Myxobrachia_ (compare pp. 23, 30; also L. N. 21, p. 519, Taf. xviii., and L. N. 33, p. 37).