OSSEOUS FISHES. 561 



great number of marine species, and many like the salmon, which 

 betake themselves to the rivers in the spawning season to deposit 

 their ova. We shall limit our remarks to the species which are 

 essentially marine, such as the Salmonidte, the Clupeadse, and a few 



others. 



SALMONID^E. 



The fishes of this family are graceful in shape, and have the body 

 clothed in scales ; they have two dorsals, the first with soft rays, fol- 

 lowed by a second, which is smaller, formed without rays, and adipose 

 that is, formed simply of a skin filled with fatty matter, unsupported 

 by osseous rays. They inhabit the seas of temperate and northern 

 regions ; ascending the rivers at certain seasons, and, in some in- 

 stances, living exclusively in the great rivers and watercourses. They 

 are found even in the most elevated mountain brooks. The grayling 

 or shad, guiniad, sprat, trout, and the salmon, the type of the family, 

 belong to the group. 



Adult Salmon. 



The genus Salmo includes three species, namely, Salmo solar, 

 8. croixj and S. trutta, the trout. Of these, S. salar (Fig. 377) has 



2 o 



