COMMON TROUT. !>7 



The Trout varies considerably in appearance in different 

 localities ; so much so, as to have induced the belief that 

 several species exist. It is, indeed, probable that more 

 than one species of River Trout may exist in this country ; 

 but when we consider geologically the various strata tra- 

 versed by rivers in their course, the effect these variations 

 of soil must produce upon the water, and the influence 

 which the constant operation of the water is likely to pro- 

 duce upon the fish that inhabit it ; when we reflect also 

 on the great variety and quality of the food afforded by 

 different rivers, depending also on soil and situation, and the 

 additional effect which these combined causes in their various 

 degrees are likely to produce ; we shall not be much sur- 

 prised at the variations both in size and colour which 

 are found to occur. That two Trout of very different 

 appearance and quality should be found within a limited 

 locality in the same lake or river, is not so easily explained ; 

 and close examination of the various parts which afford 

 the most permanent characters should be resorted to, with 

 a view to determine whether the subject ought to be con- 

 sidered only as a variety, or entitled to rank as a species. 

 In these examinations the character of the internal organs 

 also, and the number of the bones forming the vertebral 

 column, should be ascertained. The normal number of ver- 

 tebra? in Salmo fario, our Common Trout, I believe to be 

 fifty-six. 



The remarks of Lord Home on the Common Trout are 

 as follows : " I am much inclined to think there is but one 

 kind of River Trout ; the large Lake Trout may be different, 

 but of that I can be no judge, having never caught or seen 

 them ; but to the variation in size, colour, and appearance of 

 the River Trout I can speak. It has often happened to me, 

 when fishing in the height of the season for Trout in Tweed, 

 that, out of two or three dozen I have caught, there should be 



VOL. II. H 



