THE SLIPPER ANIMALCULE 13 



eral specimens to see if the vacuoles are con- 

 stant in number and position. What is their 

 shape when expanded ? "When contracted ? 

 Are they in the ectosarc or endosarc ? 



5. The nucleus (better called the macronucleus). 



— What position has it? Shape? Structure? 

 If the nucleus be not easily seen, treat the 

 specimen with stains as directed for AnuBba. 

 After staining look for a small body, the 

 paranucleus (better called the micronu- 

 cleus), lying by the side of the nucleus. 

 How does the nucleus of this animal com- 

 pare in shape and size with that of Amo&ba ? 



6. The cilia. — Are they found covering all parts of 



the body ? How do you prove this or the oppo- 

 site ? Do they have any definite arrangement ? 

 Are there any variations in size ? Is there any 

 connection between the ectosarc and the proto- 

 plasm composing a single cilium? Examine 

 the form, structure, length, and diameter of a 

 single cilium. This may best be done in ani- 

 mals killed with one per cent, osmic acid or one 

 per cent, acetic acid, or on specimens stained 

 with iodine. Considering form and size, how 

 many kinds of cilia can you distinguish? Make 

 enlarged drawings of the various kinds. 



7. The trichocysts (seen lying directly beneath 



the cuticle). — How are they arranged ? What 

 is their shape ? Structure ? 



8. The mouth. — What is its position ? Shape ? Is 



the position constant? Is the shape perma- 

 nent? How is the mouth closed? Compare 

 with Amceba in these various respects. Why 

 does Paramecium have a mouth ? 



