M. E. Claparede on Actinophrys Sol. 289 



wall, and very regularly arranged. If they be granules, they 

 might even be regarded as nuclei, of a nature quite different 

 from that of the so-called nucleus oi LoxodeSy^hioh. would then 

 probably have to be regarded as quite a different organ. But, 

 not to dwell any longer upon mere suppositions, let us pass to 

 the VorticellcB. How can these animals, with their composite 

 structure, their bell, their nucleus, stalk, muscle, &c., be de- 

 scribed as unicellular ? The muscle of a Vorticella is evidently 

 as distinct and independent an organ as any muscle in a higher 

 animal. It even possesses the second elementary tissue, the elastic 

 cylinder. Even the cilia of the true Infusoria indicate a much 

 higher organization than that of an unicellular creature, and I 

 do not think that they can be regarded as mere excrescences of 

 a cell. It is very probable that both nerves and muscles exist, 

 although our present instruments are insufficient for their dis- 

 covery. The movements of the cilia in the Infusoria cannot be 

 compared with those of a ciliated epithelium. The latter goes 

 on involuntarily throughout the life of the animal, and some- 

 times does not cease even with its death. In the Infusoria, as 

 in the Rotatoria, on*the contrary, the movement of the cilia is 

 entirely voluntary. No one, in fact, can overlook the great 

 similarity of the ciliary apparatus of the Infusoria with that of 

 the Rotatoria, but no one will regard the latter as mere append- 

 ages of cells ; from these to the tentacles of the Polypes is only 

 a single step. In short, it is equally impossible to regard a 

 Vorticella or a Stentor, and a Hydra^ or any other Polype, as a 

 single cell. 



We have already proved that the Rhizopoda are not single 

 cells; but what are the arguments in favour of their multi- 

 cellular constitution ? Dujardin, true to his theory, has chosen 

 the name sarcode with great judgment, to express a substance 

 which he considered to replace the muscles of the higher animals. 

 But this cannot be the only function of sarcode ; — it must also 

 act like nervous matter in conducting sensation and will; it 

 must separate the fluid which serves for the solution of the ali- 

 mentary matters, and secrete various materials like horn or 

 chitine {Arcella), or adhesive substances {Diffluyia, &c.), for the 

 formation of the shell ; in short, it must be able to perform all 

 the functions necessary for the support and propagation of the 

 animal. It is very difficult to understand how a structureless 

 mass can secrete two quite different substances in the same 

 animal (as, for example, in Arcella), one of which solidifies into 

 a shell, whilst the other serves for the solution of nutritive 

 matter. The numerous functions performed by these organisms 

 render it highly probable that this, so-called, amorphous, struc- 

 tureless mass will be found to be of a more composite nature, 



A7in. §• Maff. N. Hist. Ser. 2. Vol, xv. 19 



