136 RHIZOPODA :-AM(EBA j ACTINOPHRYS. 
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 Ehizopoda , 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 Actinophrys 
(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 
