THE SMELT 309 



has about the same specific gravity as water, but will be se- 

 verely bent as they leave it. This accounts for the small dis- 

 tance between the lens and the retina. 



The smelts belong to the bony fishes and are related to the 

 trout. They are preeminently inhabitants of the northern 

 temperate zone, since all but one of the ten genera occur only 

 there. They are small marine fishes, and although a few are 

 inlrabitants of the deep sea, most live near the shore, and in the 

 spring ascend rivers to spawn. Some of them have become cut 

 off from descending to the sea, and live permanently, as " land- 

 locked " forms, in fresh water. Such " land-locked " uidi- 

 viduals are of smaller size than the marine ones. The food of 

 smelts, like that of other salmons, is chiefly animal, consisting 

 of smaller fishes or insects, small crustaceans, and mollusks. 



Smelt are of considerable economic importance, since they 

 share with other members of the salmon family a delicately 

 flavored flesh. Our Atlantic form {Osmerus'^ mordax-), which 

 ranges from Delaware Bay northward, is caught most abun- 

 dantly in Maine. The total Atlantic smelt fishery is valued at 

 •1125,000. Smelt eggs are artificially hatched and planted in 

 rivers previously uninhabited by them. Smelt are said to 

 return to these rivers after spending the winter in the sea. 



The family Salmonidse, which in its widest sense includes 

 the smelts,^ comprises some of our most important food fishes. 

 It is distinguished from other families of spineless finned fishes 

 by having both ventral {v.f, in Fig. 284) and adipose fins (rf./, 

 Fig. 284) present. The head is naked, but the body is scaly 

 and rounded. 



1 osm.erus, odorous ; the Greek name is the equivalent of the English "smelt." 



2 Biting. 



' By recent authors the smelts are assigned to a distinct family, the Argen- 

 tinidcc. 



