CHAP. XVI.] 



THE BRITISH ISLES. 



321 



The following is a list of the birds now held to be peculiar to 

 the British Isles : — 



1. Parus britannicus ...Closely allied to P. ater of the continent ; a local 



race or sub-species. 



2. Parus rosea Allied to P. caiidafus of the continent. 



3. Lagopus scoticus Allied to L. albus of Scandinavia, but very distinct. 



Freshwater Fishes. — Although the productions of fresh waters 

 have generally, as Mr. Darwin has shown, a wide range, fishes 

 appear to form an exception, many of them being extremely 

 limited in distribution. Some are confined to particular river 

 valleys or even to single rivers, others inhabit the lakes of a 

 limited district only, while some are confined to single lakes, 

 often of small area, and these latter offer examples of the most 

 restricted distribution of any organisms whatever. Cases of this 

 kind are found in our own islands, and deserve our especial atten- 

 tion. It has long been known that some of our lakes possessed 

 peculiar species of trout and charr, but how far these were un- 

 known on the continent, and how many of those in different 

 parts of our islands were really distinct, had not been ascertained 

 till Dr. Giinther, so well known for his extensive knowledge of 

 the species of fishes, obtained numerous specimens from every 

 part of the country, and by comparison with all known con- 

 tinental species determined their specific differences. The 

 striking and unexpected result has thus been attained, that 

 no less than fifteen well-marked species of freshwater fishes 

 are altogether peculiar to the British Islands. The following 

 is the list, with their English names and localities : — ^ 



Freshwater Fishes peculiar to the British Isles. 



Latin Name. 



1. Salmo brachypoma.. 



GALLIVENSIS . 

 ORCADENSIS .. 

 FEROX 



English Name. 



Short-headed salmon 



Galway sea-trout 



Loch Stennis trout . . 

 Great lake-trout 



Locality. 

 Firth of Forth, Tweed, 

 Ouse. 



Galway, West Ireland. 



Lakes of Orkney. 



Larger lakes of Scot- 

 land, the N. of Eng- 

 land, and Wales. 



1 The list of names was famished to me by Dr. Giinther, and I have 

 added the locjalities from the papers containing the original descriptions,' 

 and from Dr. Haughton's British Freshwater Fishes. 



Y 



