RHIZOPODA :—FORAMINIFERA. 137 
with one of these threads, it is usually held by adhesion to 
it, and the filament forthwith begins to retract itself; as it 
shortens, the surrounding filaments also apply themselves to 
the captive particle, bending their points together, so as gra- 
dually to inclose it, and themselves retracting until the prey 
is brought to the surface of the body; and the substance of 
the threads being itself drawn into that of the body, the 
entrapped particle is embedded along with this, and under- 
goes digestion in the surrounding sarcode, any indigestible 
particle being subsequently extruded from the surface of the 
body, just as in the Amaba. The reproduction of these 
creatures, so far as is yet known, is effected by self-division, 
like that of the Jnfusoria (§ 135); but there is reason to 
believe that a “conjugation,” or reunion of two individuals, 
sometimes occurs, and that this is to be looked on as repre- . 
senting the sexual propagation of higher animal. 
* Fig. 78.—FoRAMINIFERA. 
A, Oolina; B, C, Nodosaria; D, Cristellaria; E, Polystomella; F, Dendritina, 
G, Globigerina; H, Textularia; I, Quinqueloculina. | 
131. This Rhizopod type of animal life is manifested in 
two groups of great interest, which are characterised by 
the possession of hard shells, formed by the consolidation 
of the external layer of sarcode. The Foraminifera have 
calcareous shells, which often bear a strong resemblance to 
those of Nautili, &c. in miniature (fig. 78), but which really 
have an entirely different relation to the animals that form 
them. For whilst the Nautilus occupies only the last or 
outer chamber of its shell, the chambers previously formed 
