136 RHIZOPODA : AIKEBA; ACTINOPHRTS. 



organization is so low, that there is not even that distinct 

 differentiation into containing and contained parts which is 

 necessary to constitute a cell ( 32) ; for although the super- 

 ficial layer of the sarcode possesses more consistence than the 

 interior, it is nevertheless obvious that it has not the tenacity 

 of a membrane, since (as will be presently seen) it does not 

 oppose the passage of solid particles into the interior. How- 

 ever inert this creature may seem when first glanced at, its 

 possession of vital activity is soon made apparent by the 

 movements which it executes and the changes of form it 

 undergoes; these being, in fact, parts of one and the same 

 set of actions. For the shapeless mass puts forth one or 

 more finger-like prolongations, which are simply extensions 

 of its gelatinous substance in those particular directions; 

 and a continuation of the same action, first distending the 

 prolongation, and then, as it were, carrying the whole body 

 into it, causes the entire mass to change its place. After 

 a short time another prolongation is put forth, either in the 

 same or in some different direction ; and the body is again 

 absorbed into it, so as to shift its place still more. It is by 

 means of this movement that the creature obtains its supplies 

 of food ; for when, in the course of its progress, it meets with 

 a particle appropriate for its nutriment, its gelatinous body 

 spreads itself over this, so as to envelope it completely ; and 

 the substance (sometimes animal, sometimes vegetable), thus 

 taken into this extemporized stomach, undergoes a sort 01 

 digestion therein, the nutrient material passing into the sub- 

 stance of the sarcode, and any indigestible portion making its 

 way to the surface, from some part of which it is (as it were) 

 finally squeezed out. 



130. Many other forms of this group, which has received 

 the designation of Rhizopoda, have less power of moving from 

 place to place, but obtain their food by a modification of the 

 same arrangement : of this we have an example in ActinopJirys 

 (fig. 77 B). The body being stationary, its gelatinous substance 

 extends itself into long filaments, termed pseudopodia : these 

 often divide themselves again like the roots of a tree (whence 

 the designation of the group), so as to form threads of ex- 

 treme tenuity; and sometimes these threads meet again and 

 coalesce, so as to form a sort of irregular network. When any 

 minute animal or vegetable organism happens to come in contact 



