146 DR. SCHULTZE, ON THE RHIZOPODA. 



A. porrecta, and gives a figure of it (Plate VIII. fig. 18). In 

 this form filamentary processes are sent out from all parts of 

 the colourless body. These processes are of some width at 

 their commencement, and soon subdivide into branches. Their 

 length is sometimes eight or ten times that of the body, and 

 they ultimately become so fine that their terminations can 

 only be distinctly seen with a magnifying power of 400 

 diameters. The form and extension of the body changes 

 every moment, according as the diffluent substance is thrown 

 out into these processes. If two of the processes come in 

 contact with each other they coalesce, forming broadish plates 

 or reticular meshes, which, the change of figure never ceasing, 

 are either retracted into the common mass of the body or are 

 enlarged by additional protrusion of its substance. A con- 

 tinued current of the granules imbedded in the contractile 

 substance accompanies all these phenomena ; and in the pro- 

 cesses this current follows two directions. On one side the 

 globules may be seen advancing towards the end of the pro- 

 cess, where they turn round, and are carried with a compara- 

 tively more rapid motion again towards the base of the fila- 

 ment, where they are lost in the substance of the body, unless 

 they may happen to meet another stream, by which they are 

 reconveyed through the same circuit.* 



This creature, which resembles in many respects, as will at 

 once be obvious, the well-known Actinophrys, may be taken 

 to represent the type of the Rliizopoda ; and the soft part, or 

 animal as it may be termed, of all the numerous forms in- 

 cluded in this class, is constituted in accordance with it. The 

 only essential difference, so far as is at present known, con- 

 sists in the nature and form of the more or less hard test or 

 shell. Where this test exists, it follows, as a matter of course, 

 that the body itself of the animal cannot change its form, but 

 the shell is always furnished with an opening, or with open- 

 ings, through which motile processes, exactly like those above 

 described, are protruded and moved. Thus, in the ArcellcB 

 and Dlfflugice, abounding in fresh water, finger-shaped pro- 



" The same apparent circulation of granules is observable in the reti- 

 cular filaments in the body of NoctUuca miliuris, first pointed out by M. 

 de Quatrefages ; but the reality of which, in the uninjured condition of 

 the animal, Mr. Huxley (' Quarterly Journal of Microscopical Science,' 

 Vol. iii., p. 51) seems inclined to dispute. Our own observations, how- 

 ever (though not very numerous), would lead us to imagine that M. de 

 Quatrefages' account is correct. If so, the remarkable similarity of the 

 movement in those filaments in NoctUuca with that observed in the 

 Ehizopods should not be lost sight of, nor the apparent correspondence of 

 the motions of the particles in or on them, with that which may be wit- 

 nessed in the nuclear currents, or mucous strings, in the cyclosis in certain 

 vegetable cells ; as, for instance, in the hairs of Tradescavtia. 



