WORMS, MOSS-POLYPS, SPONGES, ETC. 117 



interesting mites whose life-history we are now 

 prepared to read. 



Placed in the field of a microscope, these shells 

 exhibit on their surfaces innumerable punctfe or 

 dots, which are in reality miiiute pores leading 

 through the shell into the interior. Through these 

 pores the animal substance that is contained within 

 may be extended in the form of delicate processes, 

 known as false feet (pseudopodia), by means of 

 which the currents of food-particles may be di- 

 rected to the organism. The bulk of the animal 

 itself consists of a tiny bit of jelly-like substance, 

 known as protoplasm, which shows none of the 

 organs that are common to the higher animals; 

 that is to say, there is neither mouth, stomach, 

 heart, nor nerve. But despite these deficiencies the 

 animal passes through the cycle of life with a free 

 and satisfactory performance of the usual processes 

 of assimilation, growth, and reproduction. There 

 are few kinds of animals that are simpler in struc- 

 ture than these so-called pore-bearers (Forami- 

 nifera), and one of these is the almost universally 

 distributed proteus-animalcule of our fresh waters 

 (Amoeba), which differs only in the absence of a 

 shell. 



The simplest form of foraminiferal shell is a 

 hollow sphere, in which the protoplasm, or active 

 animal substance, is lodged. In other forms this 

 primitive sphere buds out into a number of addi- 

 tional spheres, which gradually increase in size 

 from the oldest to the newest, and may develop 

 either one in advance of the other in a straight 



