210 



GILLAROO. 



GIZZARD TROUT. 

 Gilla/roo Trout, Thompson ; Nat. Hist, of Ireland, vol. iv, p. 154. 



The Gillaroo is usually set down as a variety of the Common 

 Trout, from which the ordinary supposition has been that it 

 is only distinguished by a particular firmness, or gizzard-like 

 structure of the coats of the stomach; and it has been further 

 believed that this thickness of the stomach is caused by its 

 habit of feeding on shell-fish or other hard substances. Of the 

 particular structure of this organ we shall presently give an 

 account; but the alleged cause appears the more doubtful, as 

 it is found in this fish in its very young condition, and the 

 ordinary Trouts which inhabit the same rivers, and at least 

 occasionally devour the same substances, are without this par- 

 ticular form of the organ. It appears that the fishermen are 

 well able to distinguish between the Gillaroo and the Common 

 Trout; and, for myself, (having been favoured by the kindness 

 of the noble Earl of Enniskillen, whose promptitude in fur- 

 nishing me with supplies of this and other fishes of Ireland 

 demands my earnest acknowledgments,) from a close examination 

 of them I feel no hesitation in expressing my opinion that 

 this is a distinct species from the Common Trout; and in this 

 it is a satisfaction to find myself supported by Mr. Thompson 

 in the work above referred to. That the instinct of this fish 

 may lead it to feed more freely on river shell-fish than the 

 Common and Lake Trouts which frequent the same rivers, is 

 highly probable; and it is probably better able than they 

 to crush and digest them; but it also takes freely a fly 

 and worm, and it is to be regretted that its other more 

 peculiar habits have not hitherto been closely studied. It is 



