PARAMCECIUM (Slipper Animalcule). 



Phylum I, PROTOZOA; class 5, INFUSORIA; order i, CILIATA. 



HABITAT. Paramcecia are fairly common in stagnant pools, but 

 become noticeably abundant only when putrefaction of contained 

 organic matter sets in. They may be secured for laboratory purposes 

 by partly filling a glass jar with hay or dead leaves, covering it with 

 water and allowing it to stand in a warm room for several days. The 

 appearance of a scum and the characteristic odor of decaying organic 

 matter indicate the probable presence of Paramcecia. A jar of water 

 that has contained clams soon swarms with Slipper Animalcules. 



APPEARANCE. An individual Paramcecium is just on the limit of 

 unaided vision, appearing as a minute white speck moving about in a 

 drop of water that is held against a dark background. When properly 

 magnified it is seen to be slipper-shaped, the rounded end correspond- 

 ing to the heel and the more pointed end to the toe. The typical speci- 

 mens are more or less cylindrical. 



Technical Note. With a pipette or camel's hair brush, place on a clean 

 glass slide a drop of water containing a little of the scum from a jar 

 prepared under conditions suggested above. Cover, and study first 

 with a low power, later with a higher power of the microscope. 

 If the animalcules dart about too rapidly to be readily followed, their 

 movements can be retarded by adding a thin mixture of cherry gum 

 and water. A few fibers of cotton enclosed between the cover and 

 slide will serve both to hinder free movement and to prevent excessive 

 cover-glass pressure. 



MOVEMENTS. Study their movements until you can answer the 

 following questions: Which end of the body is directed forward hi 

 progression ? Does the animal ever move backward ? Is there any 

 other motion? Does the shape of the body ever change? 



STRUCTURE. Note the following relations and parts: 

 a) An anterior and a posterior end, determined by the student in 

 the observations suggested in the preceding paragraph. 



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