48 The Natural History of the Salmon. 



frequenting their river, and more particularly, as 

 points of interest : 



1. What were the different species of Salmon in 

 the Tweed ? 



2. Did all migrate to the sea and return to the 

 river once a year ? 



3. How old were they when they first left the 

 river ? 



4. Could Salmon be detained in fresh water all 

 the year without altering their constitution and 

 condition ? 



5. What were the circumstances injurious to 

 Salmon, and hindering the "increase ? 



These were the chief objects of inquiry, but sixty 

 questions were printed and circulated. In the 

 answers the difference of opinion was most re- 

 markable. 



First, as regards the species : — 



W. Paxton, Superintendent of Tweed fisheries, 

 states that he has observed two varieties of the 

 Salmo salar besides the common one, but they 

 are both comparatively rare. The first is a very 

 handsome and large fish, distinguished from the 

 common kind by having the second dorsal or short 

 fin (the adipose fin) nearly twice as large, with a 

 very short space between it and the caudal fin^ which 

 is large and finely forked} 



^ In many of the fine salmon sent over in ice from Nova 



