466 Dr KNOX on the Natural History of 



the River Trout, of which I imagine there are at least two spe- 

 cies frequenting our rivers and lakes, I may remark, that the first 

 is the Yellow Trout ; the second I have named the Parr-Trout. 

 This latter is often confounded, even by practical fishers, with 

 the Parr, Brindlin, Fingerling or Samlet, and the mistake has 

 given rise to innumerable errors and endless disputation. In 

 their nature, habits, and locality, as I shall afterwards shew, they 

 are very distinct. Of this parr-trout one kind is found to be 

 red when opened, and is a very superior article of food to the 

 others, which are always white, however fed. The parr, though 

 in some measure unimportant in itself, by reason of its want 

 of bulk, has nevertheless received from us a degree of atten- 

 tion almost equal to that bestowed on the salmon, and which 

 seemed in some measure necessary by its supposed connexion 

 with the natural history of the salmon : its history, along with 

 that of the herling, will form a subject for a separate memoir. 

 Closely allied to the salmon is the Vendace of Lochmaben, 

 generally esteemed by naturalists as a Corregonus. This par- 

 ticular species, however, is of rare locality, confined indeed to a 

 very few lakes in Britain, of excellent flavour as an article of 

 food, and in this respect perhaps second only to the salmon. Its 

 food, as happens with so many gregarious fishes, was unknown ; 

 like the herring, to which it is also closely allied, it was sup- 

 posed by the common people to live by suction, on air and 

 water, &c. The more rational conjecture of naturalists, that its 

 food is of a vegetable nature, proved an error : we first discovered 

 and put beyond a doubt, that its usual food is the microscopic 

 entomostraceous animals with which the lake abounds. This 

 guided us in an unerring way to the discovery of the food of the 

 herring. But the history of these fishes will form the subject of 

 the Second Part of these observations. Through the fish called 

 Corregonus, of which the Vendace of Lochmaben offers a good 

 example, the Salmonidae are allied to the Clupeadaj, or the Sal- 



