172 NATURE-STUDY REVIEW [14:4— April, 1918 



and also help it somewhat in its movements. The children enjoy watching the 

 fish in the water and will soon make observations on the way the fins are used. 

 A common mistake is a belief that a fish is somehow able to dissolve water 

 into its elements hydrogen and oxygen, and thus get the oxygen to breathe; this 

 is not possible and the fish breathes the air which is mixed with the water ; the 

 fish like ourselves breathes air and thus gets its oxygen but the fish cannot 

 breath air unless it is mixed with water. In breathing, the fish constantly 

 opens and shuts the mouth thus taking the water which flows over the gills and 

 out through the gill slits. 



Lesson on a Goldfish 



i . What is the shape of a fish when seen from above? Where is the widest 

 part? What is its shape seen from the side? In how many ways is the shape 

 of the fish adapted for moving through the water? 



2. Study the covering of the fish. In which direction do the scales seem to 

 overlap? Of what use to the fish are the scales? Note a line which extends 

 from the upper part of the gill opening, along the side to the tail. 



3. How many fins has the fish? Make sketch of the goldfish with all its 

 fins and name them from the diagram on the blackboard. 



4. Which pair corresponds to our arms? Which to our legs? 



5. Describe the pectoral fins. How are they used? How do the ventral 

 fins assist the fish when simming? Study the dorsal fin. How many spines 

 has it? How many soft rays are there in it? 



6. Study the anal fin. Has it any spines in front? How many rays has it? 

 How is this fin used when the fish is swimming? 



7. With what fin does the fish push itself through the water? Are the rays 

 of the tail fin spiny or soft in character? 



8. Watch the goldfish swim and describe the action of all the fins while it 

 is in motion. In what position are the fins when the fish is at rest? 



9. Note carefully the eyes of the fish. Can you see the nostrils? Describe 

 the mouth of the fish. 



10. Is the mouth kept always in motion? Note a wide opening along the 

 sides of the head behind the gill cover. Does the gill cover move with the 

 movement of the mouth? How does a fish breathe? 



"Go with me down by the stream, 

 Haunt of bass and purple bream ; 

 Feel the pleasure, keen and sweet, 

 When the cool waves lap your feet ; 

 Catch the breath of moss and mould, 

 Hear the grosbeak's whistle bold; 

 See the heron all alone 

 Mid stream on a slippery stone, 

 Or on some decaying log, 

 Spearing snail or water-frog ; 

 See the shoals of sun-perch shine 

 Among the pebbles smooth and fine, 

 Whilst the sprawling turtles swim 

 In the eddies cool and dim!" 



Maurice Thompson. 



