COMMON TROUT. 53 



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 co- 

 lumn, should be ascertained. The normal number of vertebrae 

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

 fifty-six. 



Sir William Jardine, Bart, in a paper on the Salmonida, 

 published in the Edinburgh New Philosophical Journal 

 for January 1835, has described at considerable length the 

 variations observed in the Trout of some of the lochs of 

 Sutherlandshire. Other lochs abound with Trout which are 

 reddish, dark, or silvery, according to the clearness of the 

 water. Mr. Neill, in his Tour, has noticed the black- 

 moss Trout of Loch Knitching, and Loch Katrine is said 

 to abound also with small black Trout ; an effect considered 

 to be produced in some waters by receiving the drainings 

 of boggy moors. In streams that flow rapidly over gravelly 

 or rocky bottoms, the Trout are generally remarkable for 

 the brilliancy and beauty of their spots and colours. Trout 

 are finest in appearance and flavour from the end of May 

 till towards the end of September; an effect produced by 

 the greater quantity and variety of nutritious food obtained 

 during that period. Two specimens of the Common Trout 

 taken early in January were unusually fine in colour for 

 that season of the year ; their stomachs on examination 

 were distended with ova of large size, which, from circum- 

 stances attending the capture of the Trout, were known 

 to be the roe of the Bull-Trout. The albuminous nature 

 of this sort of food, which the Trout availed themselves 

 of, was believed to be the cause of their colour ; since other 



