SALMONID^. 



649 



They are of vital importance to some tribes of the native 

 population. The European C. oxyrhynchus is as much a 

 marine as a freshwater species. In the British Islands 

 several small species occur, viz. C. chqjeoidcs, the " Gwyniacl," 



Fig. 295. — Coregonus clupeoides, 



" Schelly," or " Powen " from the great lakes ; C. vandcsius, 

 the " Vendace " of Lochmaben ; and C. idollmi, the " Pollau " 

 of the Irish lakes. The latter is brought in quantities to 

 Belfast market during the season, that is, at the time when 

 it rises from the depths of Lough Neagh to deposit its spawn 

 near the shore. Thomson says that in September 1834 some 

 17,000 were taken there at three or four draughts of the net. 

 Some of the species of the continent of Europe and America 

 attain to a much larger size than the British species, viz. to 

 a length of two feet. 



Thymallus. — Principally distinguished from Coregonus by 

 its long many-rayed dorsal fin. 



" Graylings " — five species, inhabiting clear streams of the 

 north of Europe, Asia, and North America. The best known 



