10 



H aw aiian Fishes 



tubes just beneath the surface of the body. The most conspicuous of these 

 tubes runs from the head along the side of the body toward the tail and 

 is called the lateral line. 



The bodies of all fishes are covered by a skin in which scales of vary- 

 ing kinds and numbers are implanted. These serve as a protection for the 

 fish in time of trouble and keep parasites and enemies at bay. 



The skeletons of fishes are much weaker than those of land animals 

 because they do not need to support their own weight. They, nevertheless, 

 have many of the bones of the higher vertebrates, but these bones are 

 much weaker. In the case of the sharks and rays, the bones remain as 

 cartilages throughout life and never become as hard and firm as they do 

 in other fishes. 



Fishes require energy to drive their bodies through the water in which 

 they live the same as other animals do. This energy is obtained as in 

 man from the oxidation or burning of food. They differ from man, how- 

 ever, in the manner in which they obtain their oxygen. Man takes his 

 oxygen from the air about him, while fishes obtain it by means of gills 

 from the air dissolved in the water about them. 



It is obvious that the bodies of fishes are designed to fit the conditions 

 about them. Their shape and structure have been designed to better adapt 

 themselves to the peculiar place in which they live. Very few other 

 animals are as well adjusted to their environment. 





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Drawn from Fowler 



