PRACTICAL ZOOLOGY 2/ 



feeding quietly. Otherwise their motions are likely to 

 be so rapid that study of the specimen may be quite 

 impossible. Or,, a few fibers of absorbent cotton may 

 be placed in the drop of water containing the animals, 

 thus forming meshes to entangle them. 



Aquarium Study. In the culture note the swarms 

 of animalcules, their position with reference to the sur- 

 face of the water, the sides of the dish, the direction of 

 the brightest light ; their size, color, and movements. - 



Microscope Study. With the low power study the 

 movements, their direction and rate; the flexibility of 

 the body, as seen when the animal passes through 

 narrow openings or around corners; the definite shape 

 of the body (compare with amoeba) ; the nervous prop- 

 erties, especially the sense of touch exhibited when the 

 animal comes into contact with a foreign body ; the 

 tendency to collect around food masses and air bub- 

 bles, or near the margin of the cover glass, the latter 

 tendency best seen if the water is very foul; animals 

 in the process of fission (resembling a single speci- 

 men more or less constricted in the middle of the 

 body, Fig. 10), or in conjugation (two individuals 

 attached together by their ventral sides). 



With the high power the structure of individual ani- 

 mals and the functions of various parts of their bodies 

 may be studied. Note the arrangement, shape, size, 

 and movements of the cilia (their motions may be 

 stopped by the application of a drop of iodine solution) ; 

 the presence of the cuticle (cell wall) ; the mouth open- 

 ing leading to the gullet, the latter lined by short cilia 

 whose motions cause a current of water bearing food 

 particles to pas down into the body, where droplets 

 (food vacuoles) form and, after reaching a fairly uniform 

 size, are separated from the end of the gullet and carried 

 around through the body by the flow of the body sub- 



