GENERAL FEATURES 



51 



and almost every water boasts its own variety and sometimes several 

 varieties, of size, shape and pattern. A peculiarity in trout spots often 

 observable is that each spot has round it a pale purple-coloured halo, 

 a feature only observable in sea-trout parr and in the mature fish after 

 it has become discoloured by residence in fresh water. In small trout 

 {Jario) this halo is often very clearly marked (Fig. 5). The specimen 

 figured is a " two year old " fario which Mr. Jas. A. Muirhead kindly 

 sent me from the West of Scotland Fishery, at Bridge of Weir. It 

 was so boldly spotted as to be rather a remarkable specimen. The two 

 trout also figured (Fig. 6) show the more usual appearance of the " two 

 year old." The Norwegian river trout of 6 in. in length (Fig. 7), whose 

 photograph Mr. Abel Heywood, of Manchester, has kindly given me 

 for reproduction, may be usefully compared with the river trout 13 in. 

 in length also shown (Fig. 8), which was caught above the Falls of 

 Clyde in waters wholly inaccessible to sea-trout. The markings of 

 these fish are similar to and may be compared with those of the sea- 

 trout in Fig. 3 (i) and Fig. 4. As having a direct bearing upon much 

 that is discussed here and elsewhere in this book I have inserted two 

 plates reproducing coloured drawings of sea-trout, one fresh-run from 

 the sea (frontispiece) and the other a fish on the eve of spawning 

 (Plate IX). As a rule it may be said that superficial markings have but 

 little scientific significance in determining species, though with reference 

 to the sea-trout's external appearance one must take account of them in 

 a general description. It has, however, sometimes occurred to me that 

 a careful comparison made between the spots of the trout and sea-trout 

 respectively of various waters might help to shed a sidelight upon the 

 theory that there is only one species of trout in these islands. 



It is generally supposed, and I think with justice, that the spots and 

 markings of trout may be attributed to protective colouration. This 

 will vary greatly with environment, although Dr. Ward in his interesting 

 book on the " Marvels of Fish Life as revealed by the Camera " points 



