4 i4 NORTHERN EUROPE 



green toad ceases to exist north of latitude 58°, while the common toad is absent 

 only in the extreme north. The common newt extends up to 63° N. latitude, 

 but the crested species does not reach quite so far. 



Although the fresh-water fishes of the north are to a great 



Fishes. 



extent identical with those of central Europe, there are a certain 

 number of more or less distinctly northern types. Among these may perhaps be 

 included the asp {Aspius rapax), a member of the carp family, which, although 

 found in Austria and the adjacent countries, is common in Norway and in all 

 rivers flowing into the North Sea, whence it extends through Russia. In the 

 salmon family several of the species of charr (Salvelinus) are essentially northern 

 fishes. Charr differ from salmon and trout (Sal/mo) by the circumstance that the 

 teeth attached to the element of the palate, known as the vomer, are restricted to 

 a group at the head of that bone. Within the Arctic Circle, and as far south as 

 Iceland, there occur several kinds of migratory charr, which descend to the sea 

 in autumn and return to the river in spring to spawn. Other species, on the 

 contrary, are restricted to lakes, which they never leave ; resembling in this 

 respect the southern species. Among the migratory species is the Alpine charr 

 (S. alpinus) of Scandinavia, Lapland, and Iceland ; while a nearly allied Icelandic 

 species, S. nivalis, is non-migratory. A small Norwegian non-migratory species 

 has been named S. rutilus. Several of the salmon-like fishes of the genus 

 Coregonus are also northern, such as the Swedish C. lloydi and C. gracilis, as 

 well as C. lapponicus of Lapland, and ft widegreni of Sweden and Finland. 



