PEACTICAL ZOOLOG-Y. 



Chapter I. 

 THE PEOTOZOA. 



A PBOTOZOON is an animal which consists of only one 

 cell, the equivalent of a single cell of any of the tissues of a 

 higher animal. 



Protozoa are always of small size, and are usually micro- 

 scopic. 



I. AMCEBA. 



This protozoon is found at the bottoms of freshwater 

 pools, and in damp situations. Its indefinite and ever-chang- 

 ing shape is characteristic, and has gained for it the name 

 ' proteus animalcule.' There are several forms, the largest 

 of which are just visible to the naked eye, while others are 

 exceedingly minute. 



Place a drop of water containing Amoeibce on a slide : 

 cover ; and search for the animal with a low power of the 

 microscope. When found, examine it with a high power. 



A. General appearance. 



The animal is an irregular mass of protoplasm, running 

 out into blunt processes or pseudopodia, the protrusion and 

 retraction of which cause great changes in the form of the 

 cell. The pseudopodia may branch slightly. 



