THE RIVER-TROUT. 263 



or grilse state of the sea- trout, and S. gallivensis, identical 

 with the estuary trout of Knox. 



Dr. Day gives one species and eight varieties, viz., 

 Salmo fan'o, with Loch Leven trout, Grasspuil trout, 

 Estuary trout, Orkney trout, Cornish trout, Great Lake 

 trout, Gillaroo trout, and Swaledale trout, as varieties. 



Yarrell gives three species, Salmo fario, S. ferox, and 

 S. levenensis. 



The river-trout varies in colour and shape according 

 to the river which it inhabits. This variation arises in a 

 great measure from local circumstances. Trees or bushes 

 overhanging the stream, gravel or mud in its bed, great 

 or less amount of light, depth of water, distribution and 

 quality of food, all go to alter the condition and aspect of 

 the fish. 



The trout in one part of the river may be silvery and 

 marked with many dark cross spots, and with very red 

 flesh ; whilst in another part they are yellow-sided, red 

 spotted, and with white flesh. Change the fish from one 

 to the other locality, and they in a very short time take on 

 the local form and colour. 



In the year 1867 two separate lochs in Scotland were 

 stocked with trout from Loch Morar, both lochs being 

 about 1500 feet above the level of the sea. In the one, 

 possessing a sandy and weedy bottom, we caught, in 1882, 

 a great many trout up to a pound weight. They were long 

 lanky fish, their sides and under-surface having a golden 

 tinge. The spots were numerous and red, and the flesh 

 white. 



In the other loch, not two miles away smaller, not 

 very deep, with a very rocky bottom the fish do not ex- 

 ceed J Ib. to I Ib. in w r eight, are very dark in colour, with 

 yellow sides, covered with purple and red spots, and the 

 flesh pink. So altered were these fish from those caught 

 in Loch Morar, owing to changed conditions of life, that 

 they might easily be considered as distinct species. 



" In the streams and cuts through the flat bogs below the 

 high land, there are large, blackish fish, locally known as 

 bog-trout. In the spring of the year, when the bog-holes 



