VARIETIES OF TROUT. 77 



from the influence of food and other causes, 

 they became changed ; the young trout of the 

 introduced variety had flesh less red than 

 their parents ; and in about twenty years the 

 variety was entirely lost, and all the fish were 

 in their original white state. A very specula- 

 tive reasoner might certainly defend the hy- 

 pothesis, of the change of species in a long 

 course of ages, from the establishment of par- 

 ticular characters as hereditary. It might be 

 said, that trout, after having thickened their 

 stomachs by feeding on larvae with hard cases, 

 gained the power of eating shell-fish, and were 

 gradually changed to gillaroos and to char ; 

 their red spots and the yellow colour of their 

 belly and fins increasing. In the same manner 

 it might be said, that the large trout which feed 

 almost entirely on small fishes gained more 

 spines in the pectoral fins, and became a new 

 species ; but / shall not go so far, and I know 

 no facts of this kind. The gillaroo and the 

 char appear always with the same characters ; 

 and I have never seen any fish that seemed 

 in a state of transition from a trout to a gillaroo 

 or a char ; which, I think, must have been the 



