Fishes. 4663 



between the bridge and the Solway Frith, into which the Nith pours 

 its waters. They have been taken also in the estuary of the Forth, 

 and, as I have been assured, In the brackish waters of the Esk, in 

 Eskdale, Yorkshire. They were generally about a foot in length, al- 

 though I have seen taken, and examined one which weighed four 

 pounds, a weight which no doubt the greater number would reach but 

 for the constant net-fishing which prevails in these waters. That the 

 young of these trout were also in the net at the time the larger were 

 captured is extremely probable, as some of the nets took everything 

 down to the minnow and herring fry ; but the young of all the Sal- 

 monidse bearing a close resemblance to each other did not then receive 

 from me all the attention the subject merits. Agreeing so far with my 

 distinguished friend M. Valenciennes, that naturalists have to do only 

 with the adult individual of any species, yet, as an anatomist interested 

 in the advance of Philosophic Zoology, I feel bound now to say that 

 neither the anatomy nor natural history of the grown individual will 

 ever enable the naturalist (whatever may be his genius or learning) to 

 place Zoology on that basis which alone entitles it to the name of a 

 Science. 



As regards its food it seems to me, after numerous examinations, to 

 live almost exclusively, during the summer at least, on a small shrimp 

 (Gammarus), which floats in innumerable shoals in these waters : these 

 shoals or groups assume the form of a cone, the apex being upwards 

 towards the stream, and generally close to some bank or abutment 

 projecting into the main stream of the river. With these small shrimps 

 I have always found the stomachs of the estuary trout gorged, and con- 

 clude that it must be the food they prefer : a draught of the net, in 

 the Nith, took several other species of the Salmonidae, and thus a 

 comparison could be and was instituted on the spot : in the true salmon 

 no food was found but the remains of the eggs of the Echinodermata ; 

 in the sea trout or Salmo fario this food was also found, but occasionally 

 the sand eel and small herring; the same remark applies to the 

 hiding : the small common river trout and the par, which were also 

 taken in the net at the same time, had been feeding abundantly on 

 flies, screws, cad bait, and all the ordinary food of the common river 

 trout which anglers know so well ; the estuary trout alone had been 

 preying on the shrimps or Gammari, and nothing else. 



As food for man these trout are excellent; their flesh is of a pink 

 colour, and quite equal to the fine river trout of England. I fancied 

 them equal in this respect to the celebrated Loch Leven trout, but 

 this is a matter of taste, which I mean not to insist on. 



