AMCEBA, VOKTICELLA, J^ARAMECIUM bi 



just on the border of vision, and is shaped somewhat Hke a 

 slipper. It may be obtained in abundance from an infusion 

 of hay. 



The body of the slipper animalcule is inclosed with a thin 

 cuticle which retains the shape of the body. All over the 

 body are longitudinal rows of minute, eyelashlike appen- 

 dages, called cilia. The Paramecium moves swiftly through 

 the water by means of the rapid vibrations of cilia. On 

 account of their rapid motion, the cilia are difficult to see in 

 a living specimen. 



On one side of the body is a long, slightly twisted groove 

 (Fig. 11), known as the oral groove, that extends into the 



Fig. 11. — Slipper animalcule much enlarged; m, mouth; g, gullet; 

 w, waste matter; /«, food vacuoles; cv, contractile vesicles; n, large 

 nucleus. 



body and finally becomes a tube. At the beginning of 

 this tube is the mouth. The Paramecium has two con- 

 tractile vacuoles, one near each end of the body. Two 

 nuclei are present, but difficult to see. 



Paramecia reproduce by fission in much the same man- 

 ner as the amoeba. There comes a time, however, when it 

 seems that the process of fission cannot be repeated again 

 until quite a different process has taken place. This pro- 

 cess is known as conjugation and may be considered a re- 

 juvenating process. Two individuals come together, and 

 an actual interchange of a part of the substance of the 



