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THE CHAR OF IRELAND. 



BY C. TATE REGAN, M.A. 

 Assistant in the British Museum (Natural History). 



In September last^ I gave an account of the Irish Char, and 

 it has been suggested to me that a short paper on the same 

 subject might have some interest for readers of the Irish 

 Naturalist. 



Char are salmonoid fishes of the genus Salvelinus, which 

 differs from Salmo- (Salmon and Trout) in having the vome- 

 rine teeth present only as a group on the head of the bone, 

 which is raised and has a boat- shaped depression behind it. 

 Within the Arctic Circle and a little to the south of it 

 migratory char are found, which descend to the sea in the 

 spring and towards the winter enter the rivers to spawn. 

 Further south all the char are non-migratory and are princi- 

 pally restricted to deep cold lakes ; on the Continent the}' are 

 found in Scandinavia and the alpine region of Central 

 Europe, and in the British Isles they occur in the lakes of 

 Scotland, the Lake District, North Wales, and Ireland. There 

 can be little doubt that when the temperature of the Northern 

 Hemisphere was lower, as during the glacial epoch, migratory 

 char were to be found much further south than at the present 

 day, and that the char of the British Isles, Scandinavia, and 

 Central Europe represent a number of lacustrine colonies of 

 one or a few migratory ancestral forms. The char of each 

 lake or each system of lakes have been isolated for a consi- 

 derable time and have become differentiated to a greater or 

 less extent ; it seems best for the present to term the different 

 forms which are recognisable ard definable ''species/' although 

 it is quite clear that they are not species in the same sense as 

 is the Pike (^Esox liicius) or the Roach {Leusisais 7'utilus), which 

 have probably persisted unchanged during the whole of the 

 time that the evolution of the Salvelini has been taking place. 



' Annals and Magazine of N^atural History (dec. 8), vol. ii., pp. 225-234. 



' Some authors iuchide SalveHnus in Salmo, but the convenience of 

 having distinct generic names for two natural groups so rich in species 

 as char and trout is obvious. 



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