236 Zoological Society : — 



1. In specimens from Loch Grannoch the male fish has the colours 

 of S. salvelinus, Donov. ; the female those of S. alpinus, Donov. 

 The male has a much larger head and larger fins than the female. 

 Number of ova, 500. 



2. In specimens from Lough Melvin both sexes are coloured 

 alike ; nor can they be distinguished from each other by the size of 

 the fins. Number of ova, 959. 



The differences observed in the Charrs from the other localities 

 are not pointed out. Certainly, if Mr. Thompson had really seen 

 those in the size of the scales and of the teeth, he would have men- 

 tioned them, and probably arrived at a different conclusion ; but 

 having found that some authors before him distinguished the species 

 by the coloration as the chief character, and having satisfied him- 

 self that there is a great difference in this respect between the two 

 sexes in the Loch-Grannoch fish, he did not make any further di- 

 stinction between the other differences he was aware of, between ac- 

 cidental differences of individuals, between those of the two sexes, 

 and, finally, between those of the fishes from various localities, but, 

 considering all of them as equivalent, he was lost in a maze, out of 

 which there was no other escape than to cut the Gordian knot by 

 declaring those fishes to be varieties of one and the same species. 



We will not enter into a fruitless investigation as to the possibility 

 of the differences which we observe in those fishes being induced 

 by the physical peculiarities of the localities indicated by Mr. 

 Thompson. We will take and examine them as they are, and as 

 they will be, as long as zoologists of the present species of man exist, 

 provided that human interference does not put a premature termi- 

 nation to the whole tribe. We find, then, that there are other con- 

 stant differences in the Charrs from various localities, besides those 

 of individuals, age, or sex — which, derived from different parts, form 

 an assemblage of characters affording easy specific distinctions* . 

 If the difference were confined to a single character, to a slight mo- 

 dification of one organ only, I should not consider it sufficient to 

 establish a separate species on it ; if the difference consisted merely 

 in the presence or absence of white margins of some of the fins, or 

 if the fishes of one locality had only one fin-ray more, or one of the 

 fins rather more elongate, than their representatives in another locality, 

 one might call this a local variety. But if such a character is found 

 always combined with a second, or with more, so that from the one 

 an inference may be drawn as to the presence of the other, we are 

 certainly obliged to make a specific distinction. 



Thus, although we cannot agree with Mr. Thompson that the 

 Windermere, the Welsh, and the Lough-Melvin Charrs are identical, 

 we nevertheless consider his paper as highly important to our 

 knowledge of the geographical distribution of the Chans in Great 

 Britain. 



1. A Charr is found in Loch Grannoch, Kirkcudbrightshire, 

 which makes its appearance only during ten days, never before 



* Haller, in ' Correspondence of Linnaeus,' ed. by Sir J. E. Smith, ii. p. 267. 



