176 SALMONIA. SEVENTH DAY. 



scarcely any above Stockbridge. There were, four 

 years ago., many in the river just below ; but this year 

 there are very few there, and the great proportion 

 that remains is found below Houghton. I ought to 

 mention, that the water is particularly fitted for them, 

 and they become larger in this river than in their 

 native place, the Avon, some of them weighing 

 between 3 and 4 Ibs. The trout, in all its habits of 

 migration, runs upward, seeking the fresh and cool 

 waters of mountain-sources to spawn in : the grayling, 

 I believe, has never the same habit of running up 

 stream; I never saw one leaping at a fall, where 

 trout are so often seen. Their large back fin seems 

 intended to enable them to rise and sink rapidly in 

 deep pools; and the slender nature of the body, 

 towards the tail, renders them much more unfit for 

 leaping cataracts than trout and salmon. The temper- 

 ature of the water, and its character as to still and 

 rapid, seem of more importance than clearness ; for 

 I have seen grayling taken in streams, that are 

 almost constantly turbid, as in the Inn and the 

 Salza in the Tyrol. This fish appears to require food 

 of a particular kind, feeding much upon flies and 

 their larvae, and not usually preying upon small fish, 

 as the trout. It has a very strong stomach, in 

 texture like that of the gillaroo trout, and is 

 exceedingly fond of those larvse which inhabit cases, 



