EEPORT ON THE EADIOLARIA. CXXIX 



capsule, the support of the soft pseudoj)odia and the substratum of the skeleton ; the 

 calymma acts also as a hydrostatic apparatus, whilst the radiating pseudopodia are of the 

 greatest importance both as organs of nutrition and adaptation, as well as of motion and 

 sensation (§ 15). If, however, the vital functions as a whole be divided in accordance 

 with the usual convention into the two great groups of vegetative (nutrition and 

 reproduction) and animal (motion and sensation), then the central capsule would be 

 mainly the organ of reproduction and sensation, and the extracapsulum the organ of 

 nutrition and motion. 



The numerous separate vital phenomena, which by accurate physiological investigation may be 

 distinguished in the unicellular Eadiolarian organism, may be distributed in the above indicated 

 conventional fashion into a few larger and several smaller groups ; it must always be borne in mind, 

 however, that these overlap in many respects, and that the division of labour among the different 

 organs in these Protista is somewhat complicated, notwithstanding the apparent simplicity of their 

 unicellular organisation. A general classification of the groups of functions is dii3ticult, because each 

 individual organ discharges several different functions. Thus the central capsule is pre-eminently 

 the organ of reproduction and inheritance, but not less (though less conspicuous) is its importance 

 as the psychical central organ, the unit regulating the processes of sensation, motion, and also 

 nutrition. In this last respect it is comparable to the nerve-centres of the Metazoa, whilst the 

 peripheral nervous system of the latter (including the organs of sense and the muscles) are in the 

 present instance represented by the pseudopodia, which are at the same time the most important 

 organs of nutrition and adaptation. In the calymma also in similar fashion several different 

 physiological functions are united. 



203. Metastasis. — The functions of metastasis and nutrition have in all Radiolaria 

 a purely animal character, so that these Rhizopoda from the physiological standpoint 

 are to be regarded as truly unicelhdar animals, or Protozoa (" Urthiere "). Since they 

 do not possess, like plants, the power of forming synthetically the compounds (proto- 

 plasm, carbohydi-ates, &c.) necessary for their sustenance, they are compelled to obtain 

 them ready-formed from other organisms. Like other true animals they evolve carbon 

 dioxide by the partial oxidation of those products, and hence they successively take up 

 the oxygen necessary to their existence from their environment. 



The question whether the Eadiolaria are to be regarded as true anhnals I discussed fully from 

 various points of view in 1862, and finally answered in the affirmative (L. N. 16, pp. 159-165). 

 Afterwards, when in my Generelle Morphologic (1866) I sought to establish the kingdom Protista, I 

 removed the Eadiolaria along with the other Ehizopoda from the animal kingdom proper and placed 

 them in the kingdom Protista (Bd. i. pp. 215-220 ; Bd. ii. p. xxix). Compare also my Protistenreich 

 (L. N. 32) and my Natlirliche Schopfungsgeschichte (vii. Aufl., 1879, p. 364). Both these steps 

 appear fuUy justified when considered in the light of our present increased knowledge. From the 

 physiolofficcd standpoint the Eadiolaria appear as unicellular animals, for in this respect the 

 animal character of their metastasis (that proper to an oxidising organism) furnishes the sole 



(ZOOL. CHALL. EXP. PART XL. — 1886.) Er r 



