FISH. 



79 



Fish. — Fish eggs can be hatched in the school-room if kept 

 in a gem jar in clear cold water changed frequently. The 

 writer has used eggs of trout which were packed in moss and 

 received by mail. When the egg-yolk is absorbed the young 

 fish may be fed daily on boiled liver grated fine. After each 

 feeding the water must be changed to keep it clear and cool. 



Minnows may be put in the same aquarium with tadpoles 

 and snails, but it is usually better to keep fish for study in 

 aquaria or jars «by themselves as cleanliness is absolutely 

 necessary. Gold-fish and prepared fish-food can be bought 

 cheaply from the dealers. 



(From " Public School Nature Study.') 

 Diagram 0¥ a Fish. 

 A— Back Fin (dorsal). 

 B— Caudal Fin (tail). 

 C— Anal Fin. 



D— Leg Fin (pelvic). 

 E— Arm Fin (pectoral). 

 L— Lateral Line. 



Locomotion. — Buy or borrow a gold-fish, or have the boys 

 bring in a fish from the stream. Study its movements in the 

 largest glass vessel that you can get. Observe that it propels 

 itself with its tail and balances itself with the other fins. By 

 putting a rubber band over its paired fins in turn and so 

 holding them flat against the body learn the particular use of 

 each pair. 



Breathing. — Oxygen is dissolved in the water where fishes 

 live. Note the rhythmical movement of mouth and gills by 



