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. caudatus of the continent. 
3. Lagopus scoticus Allied toL. 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. Gunther, 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 : — 1 
Freshwater Fishes peculiar to the British Isles. 
Latin Name. 
1. Salmo BRACHYPOMA.. 
2. „ GALLIVENSIS .. 
3. „ ORCADENSIS . . . 
4. „ 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 furnished to me by Dr. Gunther, and I have 
added the localities from the papers containing the original descriptions, 
and from Dr. Haughton’s British Freshwater Fishes. 
Y 
