I 



trout, while in the~other Plenty fish dissected, the number 

 fell below the average for brown trout, and was under the 

 maximum for true salmon. 



The twenty-five fish from the Plenty differed somewhat in 

 size, though not more than salmon smolts under the same cir- 

 cumstances, but one noticeable feature was that the smallest 

 were the most salmon like, the larger and more developed fish 

 evidently approaching the more trout like aspect of the parents 

 and this is exactly in accordance with Dr. Giinther's obser- 

 vation, when speaking of the whole genus salmo, " that speci- 

 mens which have not attained to maturity retain a brighter 

 silvery colour, being more similar to the female fish." 



Nothing to be found in the various works on the subject 

 would lead anyone to suppose that the brown trout (Salmo 

 fario) ever exhibited a true migratory instinct, though Dr. 

 Giinther expressly says that brackish water has the effect of 

 giving them a bright silvery coat without, or with compara- 

 tively few, spots, none of which are ocellated. Yet these fish 

 do exhibit a migratory instinct, although the original parent 

 fish were detained in the ponds, and debarred from following 

 such instinct. 



