BRANCH CHORD AT A ; CLASS PISCES: THE FISHES 271 



of thirty-six feet. The smallest is the dwarf goby 

 i . 1 /is tic I i thys )7~te s s than half an inch long, found in Luzon, 

 one of the Philippine Islands. Between these extremes 

 is every variety in size, form, and relative proportions. 

 The body, for example, may be greatly elongated and 

 almost cylindrical as in the eels; or long and flattened 

 from side to side as in the ribbon-fishes; or the head may 

 be very large, wider and higher than the rest of the body 

 as in the anglers, or may have a great beak as in the 

 sword-fish. 



Body form and structure. When we consider the fish 

 as a whole, we find first a body formed for progression in 

 the water, the typical fish being pointed at each end (the 

 shorter point in front), and having the sides flattened, the 

 back and belly rather narrow, and the motive power 

 located in the fin on the tail. From this typical form 

 diverge all conceivable variations, adaptations to every 

 sort offish life. 



Most fishes have the body covered with seal eg, although 

 many have the skin naked or covered with small scales 

 so hidden in the skin as to be hardly visible. The scales 

 are small horny or bony plates which fit into small pockets 

 or folds of the skin, and are usually arranged shingle- 

 fashion, overlapping each other. They are of various 

 shapes, mostly classified as of three kinds, namely, squarish 

 enamelled scales called ganoid, roundish smooth-edged 

 called cycloid, and roundish tooth-edged called ctenoid. 



The skeleton of the fish is relatively complex. Its 

 bones are comparatively soft, having little lime in them, 

 indeed in many cases they are mere cartilage. The 

 vertebral column is made of twenty-four vertebrae in the 

 typical fishes, the number in the others being variously 

 increased, or sometimes diminished. These vertebrae are 

 of two classes, abdominal or body, and caudal or tail 

 vertebrae. The former have a neural arch which encloses 



