SALMONID^. 



last parts together forming the moveable gill-cover. The 

 different fins are sufficiently indicated by being coupled, when 

 referred to, with the name of the part of the body of the 

 fish to which they are attached. 



The external appearance of the adult Salmon during 

 the summer months, when it is caught in the estuaries 

 of our large rivers, is too well known to require much 

 description. The upper part of the head and back is 

 dark bluish black ; the sides lighter ; the belly silvery 

 white ; the dorsal, pectoral, and caudal fins dusky black ; 

 the ventral fins white on the outer side, tinged more or 

 less with dusky on the inner surface ; the anal fin white ; 

 the small, soft, fleshy fin on the back, without rays, called 

 the adipose, fat fin, or the second dorsal fin, is of the 

 same colour nearly as the part of the back from which 

 it emanates. There are mostly a few dark spots dispersed 

 over that part of the body which is above the lateral line, 

 and the females usually exhibit a greater number of these 

 spots than the males. 



These colours, differing but little, are, however, in a 

 great degree common at the same period of the year to 

 the three species that are the most numerous, as well as 

 the most valuable ; namely, the true Salmon, the Bull- 

 Trout, and the Sea or Salmon Trout ; which are also fur- 

 ther distinguished from the other species of the genus Salmo 

 by their seasonal habit of moving from the pure fresh 

 water to the brackish water, and thence to the sea, and 

 back to the fresh water again, at particular periods of the 

 year. Further specific distinctions are therefore necessary ; 

 and those that will be pointed out as existing constantly 

 in these species will, it is hoped, enable observers to iden- 

 tify not only each of these, but also the other species of the 

 genus, at any age or season. 



