22,2 Field and Forest Rambles. 



ceed to the tideways of rivers in autumn, the migration is by 

 no means general, even in rivers free from artificial or natural 

 obstructions. 



Allowing for the majority of the larger trouts being cap- 

 tured, many brooks absolutely swarm with the fish, with very 

 few exceptions not averaging over a quarter to a half pound in 

 weight, whilst in the lake from whence the brook rises, large 

 dark-coloured residents called " bull trouts," which never leave 

 it, are found, to the exclusion of the small fry. This is so 

 remarkable in some instances that the settlers account for it 

 by supposing that the adults prey on the young and expel 

 them from their haunts; hence fishermen say that more spawn 

 and fry of this and the other salmonoids are destroyed by the 

 animals themselves than by rod, line, or spear. 



Notwithstanding the varieties consequent on the external 

 surroundings, there are one or two associated brook trouts 

 which may be distinct species. For example, should the 

 following turn out to be only a race of the brook trout, it is 

 assuredly a very well-marked one. Into Lake Utopia, before 

 noticed, flows a small stream from a tarn in the vicinity. In 

 October vast quantities of the true S.fontinalis are met with 

 on their way to spawn in the tarn ; whilst in Lake Utopia, 

 the entrance of the brook, is a trout of an average smaller 

 size, of a silvery grey, profusely spotted with yellow all over 

 the back and sides, including the dorsal fins ; the lower fins 

 are white-margined, but otherwise there is a very decided 

 difference between the two sorts. The former are then heavy 

 with ova, but the light-coloured have neither the ovarium nor the 

 milt highly developed ; and as to size, individuals of the same 

 dimensions of each sort are plentiful, so that the differences in 

 colouring are not dependent on age. I could find no anato- 

 mical distinctions between the two ; and as neither can get to 

 the sea, on account of a very precipitous water-fall, and the 

 light-coloured trout seems peculiar to the lake, and is not 

 seen in any of its influent or effluent waters, but always apart 



