1HE FISH 151 



determine their shape? Are they the same color in all 

 parts of the body ? Do the fins have pigment ? 



(5) Find the lateral line on each side extending nearly 

 the entire length of the fish. Is it on the scales, in them, 

 or under them on the body ? Remove one of the scales along 

 this line and examine. Insert a needle in the place to see 

 if the line is continuous. What is its function? 



(6) Study the skin on the head next to the mouth. 

 Compare it with the skin on the other parts of the body. 

 Observe the covering of the inside of the mouth. How does 

 it dififer from that on the outside? 



Do you find teeth? Where are they located? Do they 

 have a regular arrangement? Study the shape, size and 

 firmness of attachment of a tooth. Compare it with a scale. 



Pull the lower jaw down ; this will draw out the bones of 

 the upper jaw the premaxillary bones. Study their shape, 

 size and attachment, both at the top and at the bottom. 



Draw a premaxillary bone (X4)- 



Behind the premaxillaries are the bones of the maxillary 

 proper. Observe their shape and note how they fit the pre- 

 maxillary. The lower jaw is composed of the submaxillary 

 bones which are similar to the lower jaw bones of other 

 animals. 



Do you find teeth on the upper jaw? On the lower? 

 Look in the upper part of the mouth for teeth. If teeth are 

 present there they are situated on the vomer. Find the 

 shape and size of this bone. 



Notice the covering of the tongue. Rub the finger over 

 it to ascertain the nature of the covering. Notice the 

 covering on different parts to find the variation of the 

 papillae, or taste bulbs. Do you think a fish can taste? 



