THE SALMON FAMILY 



THE fishes of this family are distinguished by having two 

 dorsal fins of which the foremost is situated near the middle of 

 the back and supported as usual by fin-rays, while the hinder, 

 placed above the ventral fin, is small and imperfect, having no 

 fin-rays. There is a peculiarity in the internal structure of 

 these fishes, which occurs also in the eels, namely, that the roe 

 in the female is not a closed sac, but is as it were split open, 

 so that the eggs when they are ripe become free in the belly 

 cavity before they escape by an opening behind the vent. 

 Different fishes of the family show a great diversity of habit. 

 With one exception in New Zealand all the species are confined 

 to regions north of the tropics, but within this part of the globe 

 some live entirely in fresh water, some feed in the sea and spawn 

 in rivers, while a few live always in the sea, some of these 

 belonging to the abyssal depths of the ocean. In Britain the 

 grayling and river trout, and the pollan, vendace, &c., of the 

 large lakes are the fresh-water forms, the salmon and sea-trout 

 the migratory. The eggs of all these are of considerable size, 

 and are heavy and non-adhesive ; they are buried by the parent 

 fish in the gravel bottoms of rivers or lakes. The smelt lives at 

 the mouths of tidal rivers, and spawns in fresh water some miles 

 from the sea. Only one marine species of the family occurs off 

 British and -Irish coasts, namely, the argentine, which has been 

 frequently taken at depths of 30 to 500 fathoms off the west 

 coasts of Ireland and Scotland. As this fish is of no commercial 

 importance, and scarcely anything is known of its habits, and as 

 the species that spawn in inland waters are outside the scope of 

 the present work, the history of the smelt alone will be here 

 considered. 



