78 



Investigations on the Life- History 

 Weight of Nusde per Standard Fish. 



Such conditions would be impossible were there a free to-and-fro 

 migration. 



5th. The close correspondence between the fish from the Helmsdale, 

 Spey, and Dee appears to indicate that these may be regarded practically 

 as one river. The experiments on marking fish at present being con- 

 ducted by Mr. Archer, so far as they go, support this idea. 





