THE VERTEBRATE ANIMALS 275 



bony vertebral column, made up of pieces of bone joined one 

 to another, forming a flexible yet strong support for the muscles 

 and protecting the delicate central nervous system. This kind 

 of an endoskeleton, or inside skeleton, is possessed by fishes, frogs, 

 turtles or snakes, and birds, and by mammals, such as the dog, 

 cat, and man. All such animals are called vertebrates. We 

 are now to take up the study of some types of various kinds of 

 vertebrates, with the view to a better understanding of man. 



Fishes 



Problem XXXIV. A study of how a fish is fitted for the life 

 it leads. . (Laboratoi-y Manual, Prob. XXXIV.} 



The Body. One of our common fresh-water fish is the bream, 

 or golden shiner. The body of the bream runs insensibly into 

 the head, the neck being absent. The long, narrow body with its 

 smooth surface fits the fish admirably for its life in the water. 

 Certain cells in the skin secrete mucus or slime, another adapta- 

 tion. The position of the scales, overlapping in a backward 

 direction, is yet another adaptation which aids in passing through 



B 



The fins of a fish : A, dorsal ; B, caudal ; C, anal ; D, pelvic ; E, pectoral. 



the water. Its color, olive above and bright silver and gold 

 below, is also protective. Can you see how? 



The Appendages and their Uses. The appendages of the fish 

 consist of paired and unpaired fins. The paired fins are four in 

 number, and are believed to correspond in position and structure 



