PARRS AND SMOLTS 25 



looking fry below the usual dimensions of those 

 which are ready to go down to the sea ; that is, till 

 the new dress comes over them, and obliterates the 

 distinguishing marks of what is called the parr. 



Secondly, That parrs are found above falls which 

 salmon can, but they cannot possibly, surmount. 



A high spate might certainly bring some of these 

 falls more to a level ; but it would be as impossible 

 for a parr to swim up them in a raging flood, as it 

 would be for the sere leaf that falls into the waves 

 to find its passage upwards. Mr. Shaw, who has 

 carefully watched shoals of parr (correctly speaking, 

 smolts) in their descent to the sea, affirms that they 

 pass down the current with the greatest caution, 

 keeping their heads up the stream, and rowing 

 gently with their fins against it, so as to steady 

 themselves and prevent a too rapid descent ; and 

 thus they drop down by degrees, tail foremost, 

 precisely in the same manner that we manage a 

 boat in the Tweed when descending the rapids. 



When the fry were congregating in May I 

 caught these little fish in various stages of the 

 growth of the new scale. In some it had super- 

 vened so as to obliterate the bars and spots entirely, 

 when their sides became silver ; in others they were 

 partially obliterated, so as to leave only a mere stain 

 of colour ; whilst some retained them almost entire. 

 As I caught these fry I sent them up to Sir David 

 Brewster, who was then residing at his beautiful 

 place on the banks of the Tweed. After a careful 

 examination he could find no distinction in the 

 structure of the organs between any of these little 

 creatures, however differing in colour. 



