138 VERTEBRATE ZOOLOGY 



tion as to which is the most primitive in structure, or as to which 

 stands nearest the orders of Ganoids. Earliest of the bony fishes 

 in geological time is the order Isospondyli, containing the allies, 

 recent or fossil, of the herring and the trout." There are twenty- 

 one families of Malacopterygii of which the best known are the 

 Elopidce (Tarpons), the Salmonidae (Salmon and Trout), and the 

 Clupeidce (Herrings). 



The Tarpon (Fig. 75) is probably the noblest member of the 

 sub-order and is often called the "Silver King." It is the favorite 



FIG. 75. Tarpon, Megalops atlaniicus, much reduced. (From Boulenger, 

 after Goode.) 



game fish along the Florida and Carolina coasts; for it is a great 

 fighter and gives the sportsman the fullest scope for the ex- 

 ercise of his skill and experience. It reaches a length of six 

 feet and weighs over one hundred pounds. Its very large sil- 

 very scales containing ganoin are used extensively in ornamental 

 work. 



The Salmon and Trout tribes are of all fishes the gamiest and 

 the most sought after by the devotee of the rod and fly. They are 

 characterized by the presence of an adipose dorsal fin. "Of all fam- 

 ilies of fishes," says Jordan, "the most interesting from every point 

 of view is that of the Salmonidse, the salmon family. As now re- 

 stricted, it is not one of the largest families, as it comprises less than 

 a hundred species; but in beauty, activity, gameness, quality as food, 

 and even in size of individuals, different members of the group stand 

 easily first among fishes." The Salmon (Fig. 76) is a marine fish, but 

 spawns far up among the small streams near the sources of large rivers. 

 This habit has given rise to the "Parent Stream Theory," according 

 to which the young Salmon go down-stream and out to sea, where they 

 remain for five years until sexually mature, and then return to spawn 



