PISCES 245 



The evolution of fishes has taken place during the ages 

 still represented by the fossil records and is therefore better 

 known than that of any phylum of invertebrates. Though 

 the exact ancestors of modern fishes are unknown, the 

 general course of events is pretty well recorded in the rocks. 

 Mariy of the ancient groups of fishes are now completely 

 extinct, and a number had peculiar characteristics which 

 died out with them. Some had the body covered with 

 heavy armor, and were provided with a rather flexible 

 neck joint, so that the head could nod. Many lacked 

 teeth and had no paired fins. Among fish-like animals 

 still in existence, tlie cyclostomes and sharks were the first 

 to appear in the past (the most primitive types came first), 

 and were followed somewhat later by the bony-fishes. 



Fisheries are of great economic importance in all parts 

 of the world. The principal species serving for food are: 

 the cod, mackerel, and salmon. In the year 1914 the total 

 catch of fish brought to Boston and Gloucester amounted 

 to 162,589,220 pounds and had a iAie of $4,395,030. 

 The total value of the fishes captured in the United States 

 and on their shores is enormous. The Bureau of Fisheries 

 is constantly at work trying to increase the productiveness 

 of fishing v and improve the quality of its output. Fifty 

 stations are maintained for propagation and study. Dur- 

 ing 1914, 4j288,757,800 eggs and young fishes were planted 

 in suitable waters. 



