334 ABDOMINAL SOFT-FINNED FISHES. 



Senegal as well as the Nile, is eighteen or twenty inches in length. 

 The Arabs call it raasch, which signifies thunder. * 



The Salmons (Salmonidde) are distinguished by a 

 scaly body, and a first dorsal fin with soft rays, fol- 

 lowed by a second which is small and adipose ; that 

 is, formed by a fold of the skin filled with fat, and 

 without rays. 



The Common Salmon (Salmo Salar) is the largest species of the 

 family. It is found in great numbers in the Arctic Seas, whence 

 it ascends rivers in large shoals every spring. It swims with great 

 rapidity, and can clear at a leap obstacles to its passage twelve or 

 fifteen feet in height. When salmon arrive at a place fit for spawning, 



FIG. 265. THE SALMON. 



they deposit their eggs in the gravel at the bottom, and then permit 

 themselves to be carried by the current to the sea ; where they go to 

 acquire strength and return again the following spring. Young 

 Salmon are therefore born in the rivers : their growth is rapid, 

 and when they attain the size of about twelve inches, they descend 

 to the sea like the adults. 



The Salmon-fishery, in many countries, forms a very important 

 branch of industry. In Norway, as many as 300 of these fishes have 

 been caught at one haul, and in the Kiver Tweed as many as 700. 

 The time selected for catching them is when they ascend the rivers 

 to spawn, for after they have deposited their eggs, and are on their 

 way to the sea, they are very lean and their flesh of little value. 



