THE BONY FISHES. 161 



then engaged in spawning. In the sea they live on small 

 shrimps. The menhaden is now put up as a substitute for 

 sardines, and is of great value as fish-bait, especially in the 

 mackerel-fishery, and for its oil. 



The family Salmonidce comprises the salmon, trout, and 

 whitefish, with a number of species and varieties. The 



FIG. 165. The Smelt, Osmerus mtrrdax. (One half natural size.) 



eastern salmon (Salmo salar) sometimes weighs eighty 

 pounds. It is common to Europe as well as Northeastern 

 America. In the autumn the salmon ascends rivers to 

 spawn, penetrating as near the source as possible. The 

 eggs are very large, exceeding a pea in size, and are laid in 



Fia. 166. The Mackerel, Scomber scrombrus. (One quarter natural size.) 



shallow holes made in the gravel of streams. The extreme 

 young is banded and called a parr; when about a year old, 

 and of a bright silvery color, before descending the rivers 

 to the sea, it is called a smolt; after its return from the 

 sea into fresh water it goes by the name of grilse; and 

 finally, after returning a second time from the sea, it a- 

 11 



