X LIST OF ILLUSTRATIONS 



FIG. tii{< page 



14. Diagram contrasting heads of female Salmon and Sea-trout - - 59 



15. Diagram of gill-covers of Salmon Trout, Grey Trout, and Salmon 



{after YarrcU, reversed) ..------ ^9 



16. Scales of a Sea-troui and a Cirilse of equal weights contrasted to 



show different rates of growth 62 



17. Vomer of a Clyde river Trout showing dentition - - - - 63 



18. Vomer of a Loch Lomond Sea-trout showing dentition - - 63 



19. Diagram contrasting outlines of tail of a Tweed " Bull Trout " 



and of a Loch Lomond Sea-trout 66 



20. "Bull Trout" (3ilb.) from the River Aln 64 



21. Scale of River Aln "Bull Trout" (,^1 lb.) indicating growth 



similar to that of a salmon grilse ------ 64 



22. " Bull Trout " (8 lb.) from the River Aln 68 



2^. Scale of River .\ln "Bull Trout" (81b.) indicating growth 



similar to that of a small summer salmon 68 



24. A Norwegian " Bull Trout " (8i lb.) 68 



25. Sea-trout eggs •74 



26. Sea-trout "eyed ova" 74 



27. Sea-trout aievins iiatching out 74 



2b. Late eggs and early aievins y^ 



2y. Sea-trout "monstrosities" (after Cicmniill) - . '7^ 



30. Scale of a late-descending Sea-trout smolt 102 



31. Scale of Sea-trout indicating a 2-winters' residence in fresh water 



prior to migration 106 



32. Scale of Sea-trout indicating a 3-winters' residence in fresh water 



prior to migration - 106 



S3- Scale ot Sea-trout indicating a 4-winters' residence in fresh water 



prior to migration - i 10 



34. Scale of Sea-trout Smolt indicating a 4-winters' residence in fresh 



water prior to migration ; [O 



35. Scale of Sea-trout indicating a 5-winters' residence in fresh water 



prior to migration ,1^ 



36. Scale of Norwegian Sea-trout indicating a 5-winters' residence in 



fresh water prior to migration , , . 



37. A typical Whitling ,j3 



38. Scale of Sea-trout illustrating period spent in the sea after descent 



as a smolt and prior to return as a whitling . - . -122 



