72 HISTORICAL PALEONTOLOGY. 



posed of an apparently structureless animal substance of an 

 albuminous nature ("sarcode"), of a gelatinous consistence, 

 transparent, and exhibiting numerous minute granules or 

 rounded particles. The body-substance cannot be said in 

 itself to possess any definite form, except in so far as it may 

 be bounded by a shell ; but it has the power, wherever it may 

 be exposed, of emitting long thread-like filaments ("pseudo- 

 podia "), which interlace with one another to form a network 

 (fig. 25,$). These filaments can be thrown out at will, and 



Fig. 25 The animal of Nonionina, one of the Foraminifera, after the shell has been 

 removed by a weak acid ; b, Crotnia, a single-chambered Foraminifer (after Schultxe), 

 showing the shell surrounded by a network of filaments derived from the body substance. 



to considerable distances, and can be.again retracted into the 

 soft mass of the general body-substance, and they are the 

 agents by which the animal obtains its food. The soft bodies 

 of the Foraminifera are protected by a shell, which is usually 

 calcareous, but may be composed of sand-grains cemented 



