PARAMECIUM 



(Materials: Carmine suspension, Sanford's red ink, Water- 

 man's blue fountain-pen ink, 15% alcohol, cotton, filter paper.) 



Classification : — Phylum Protozoa, Class Ciliata, Order 

 Holotricha. 



1. Method of Examination. 1. From the instructor se- 

 cure a drop of water from a culture coHtaining Paramecium. 

 After this has been placed on a slide, add a few cotton fibers, 

 before applying the coverglass. The fibers help retard the 

 movements of the Paramecia and thereby facilitate examina- 

 tion especially with the high power. 



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2. Examine with low power. From the instructor learn 

 how to distinguish Paramecia from other Infusoria. There are 

 several species of the genus Paramecium. The one most com- 

 monly seen in laboratory cultures is Paramecium caudatum. 



II. General Observations. 1. Describe the shape. Is it 

 constant ? Is there a plane of symmetry ? Anterior end ? How 

 determined? How does it differ from the posterior end? Note 

 a depression extending from the anterior end backward toward 

 the middle of the bod3^ This is the ora? groove. Is there a 

 dorsal (upper) and a ventral (lower) surface? Why? Notes 

 required. 



2. With ocular micrometer find length and breadth of a 

 Paramecium. 



3. Make a model in clay showing the form of Paramecium. 



4. Look for the mouth at the posterior end of the oral 

 groove. The surface bearing the mouth is called the oral surface. 

 Make an outline drawing 60 mm. long, showing oral view. The 

 mouth should be about equidistant from the lateral margins of 

 the body in this drawing. The surface opposite the oral surface 

 is called the aboral surface. 



5. Draw lateral view in outline, 60 mm. long. 



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