80 THE NATURE STUDY COURSE. 



means of which the fish bathes its gills with currents of water. 

 This is its breathing. Explain that the red fringes of the 

 gills do the same work for the fish that our lungs do for us. 

 Infer the necessity for the frequent change of water in the 

 fish jar. When a fish is left too long in unchanged water it 

 pants for breath by moving its gills very fast. 



The fish's sense of smell is located in its nostrils. With a 

 bristle try to reach the mouth cavity of a dead fish through 

 the nostril. Infer that this organ takes no part in breathing. 



In studying the fish it is well to have a dead one for 

 comparison. Has the fish eye-lids 1 Can it wink or shut its 

 eyes? Can it roll its eyes around and look downward or 

 upward or back ? Can it turn its head ? Account for the 

 zigzag manner in which a fish swims. 



Feed the fish and watch it take the food. Examine the 

 teeth in the dead fish's mouth. 



Notice the scales, their arrangement, their edges, their 

 shapes. Do they give the color to the fish's body 1 Where 

 is the color darker 1 Being darker above they are less easily 

 seen. Some fishes, as the catfish, like the frog, can change 

 their color to suit their surroundings. 



What advantage to the fish is its pointed wedge-shaped 

 body ? Observe the forking of the tail and the muscular part 

 of the fish that controls it. 



Spiders. — The study of the spider is prescribed in the 

 Manitoba course. Foolish, although not inexplicable, pre- 

 judice exists against spiders, toads, garter-snakes and bats. 

 It is worth while conducting studies on these interesting and 

 useful animals if for no other reason than to remove the 

 hatred and fear with which so many people regard them. 



Some spiders are attractive on account of the remarkable 

 beauty of their bodies, others for the wonderful webs which 



