148 ZOOLOGY. 



It constantly alters its shape, pushing out from various 

 parts of its substance blunt, finger-like processes, deno- 

 minated pseudopodia (Gr. pseudos, false; poda, feet). 

 These pseudopodia procure food for the animal, and en- 

 able it to change its position slowly. When a pseudo- 

 podium comes in contact with some particle of animal or 

 vegetable matter, it surrounds it with its jelly. The rest 

 of the sarcode flowing up to this point, the food is in- 

 closed in the substance of the body, where it is digested. 

 It soon pushes out another process in a different direc- 

 tion, when a similar result follows. Sometimes six or 

 eight pseudopodia are sent out at the same time. In this 

 way food is procured, and locomotion effected simulta- 

 neously. As it is destitute of excretory organs, indiges- 

 tible particles are pushed out through the sarcode. 



The outer layer of the body, termed the ectosarc (Gr. 

 ecto, without ; sarx, flesh), is a little more solid than the 

 interior, which is called the endosarc (Gr. endo, within). 



Each particle of food carries with it a little globule of 

 water. These globules are visible in the interior of the 

 animal, and were formerly believed to be stomachs. A 

 contractile vesicle, similar to that observed in the Infu- 

 soria, has been found in the Amoeba. It is filled with 

 some clear fluid, and contracts and expands at pretty 

 regular intervals. There is also a nucleus, which some 

 suppose to be connected with reproduction : but there is 

 no certain knowledge on this point. 



The most usual mode of reproduction which has been 

 observed is by fission, or self-division. The animal in 

 certain cases splits into two parts, each of which becomes 

 a distinct individual. Occasionally, a detached pseudo- 

 podium is developed into a separate animal. 



216. (2.) The Foraminifera (Lat. foramen, a hole; 

 feroy I bear) differ from Amoeba in being covered with a 

 shell which is usually calcareous, although in rare cases 

 it is composed of particles of sand united together. These 

 shells assume a great variety of forms, and many of them 

 are extremely beautiful. They are so exceedingly small 



