Fishes. 



4667 



i.e. by 1, red spots; 2, dark spots; 3, par markings; 4, silvery 

 scales. 



Subfamilies. — Adult. 

 * 1. Trout. 2. Sea Trout. 3. Salmon. 



Red spots or dark spots, 

 as the case may be. The 

 red-spotted prevail in ri- 

 vers ; one species frequents 

 the estuary : the dark-spot- 

 ted trout are lacustrine 

 generally. 



Colouring. 



Many dark spots above 

 and below the lateral line. 

 By so much as the fish is 

 silvery and scaly and with 

 few spots, by so much does 

 he approach the pure sal- 

 mon, and in health he loses 

 all the red spots. 



Silvery scales ; a few 

 dark spots above the la- 

 teral line. When the dark 

 spots below the lateral line 

 amount to five or six, the 

 salesman knows that the 

 fish is coarse, and that it 

 approaches the Fario in 

 character. The specific 

 character, then, of the very 

 fine salmon is to lose all 

 the spots of every kind. 



Lastly, for I am unwilling to extend this memoir further, species no 

 doubt exist or have existed approximating all these species and sub- 

 families, leaving no gap or deficient link in the serial unity of the 

 family ; and these species will be found to be characterised, not by 

 any new feature, not by any character wanting in the young, but the 

 predominance of one to the exclusion and extinction of the others. 

 The embryo, the young, is perfect generically ; the adult specifically. 

 This is the law of species, and this is no doubt the law by which 

 Nature provides for the extinction of certain species and the ap- 

 pearance of others in time and space. Were our observations 



* Fig. 11. a, marks the vomerine teeth in the trout and in the young of all the 

 the species of the Salmonidae. Fig. 12. a, vomerine teeth in the sea trout: the young 

 salmon from 2\ to 3 lt>s. weight has the dentition of the sea trout. Fig. 1 3. a, vomerine 

 teeth in the full-grown salmon : the transverse vomerine teeth remain ; the mesial 

 and posterior are reduced to one or two. 



