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PROTOZOA THE SIMPLEST ANIMALS. 



Fourth Type — Paramecium. 



Paramceaum, a type of Infusorians, especially of those 

 which are uniformly covered with short cilia (Holotricha). 



Description. — Specimens of Paramtzcium may be readily 

 and abundantly obtained by leaving fragments _ of hay to 

 soak for a few days in a glass of water. A few individuals 

 have been lying dormant about the plant; they revive 

 and multiply with extraordinary rapidity. They are also 

 abundant in most stagnant pools, and are just visible when 



COD. 



"&d. ^ iv - 



Fig. 37. — Paramcecium. — After Btltschli. 



ad. Adult form, showing cilia, "mouth," contractile vacuoles, etc. 

 div. Transverse division. 

 con. Conjugation. 



a test-tube containing them is held between the eye and 

 the light. Their food consists of small vegetable particles. 

 The form is a long oval, with the blunter end in front ; 

 the outer portion of the cell-substance is differentiated into 

 a dense rind or cortex, with a delicate external cuticle, 

 perforated by cilia. There is a definite opening, the so- 

 called mouth, which serves for the ingestion of food 

 particles ; and there is also a particular anal spot posterior 

 to the mouth, from which undigested residues are got rid of. 



