262 FISHES. 



genera are characteristic of the Arctic fauna : marine species 

 of Cottus ; Centridcrmichthys, Icclus, Triglops ; Agonus, Aspi- 

 dophoroides ; Anarrhichas, Centronotus, Stichmus ; Cydopterus 

 and Liparis. Two species of Sehastes are rather common. 



Characteristic is also the development of Gadoid fishes, of 

 which some thirteen species, belonging to Gadus, Merluccius, 

 and Molva, form one of the principal articles of food to the 

 inhabitants of the coasts of the Arctic Ocean. The Blennioid 

 Anacanthini or Lycodidce, are limited to the Arctic and An- 

 tarctic coasts. Ammodytes and a few Flat-fishes {Hippo- 

 glossoides and Pleuronectcs) are common in the more temperate 

 parts. 



Labroids only exceptionally penetrate so far towards the 

 north. 



Physostomes are veiy scarce, and represented only by a few 

 species of Clupca and by Mallotus; the latter is an ancient in- 

 habitant of the Greenland coasts, fossil remains, indistinguish- 

 able from the species of the present day, being frequently 

 found in nodules of clay of comparatively recent formation. 



The Arctic climate is still less favourable to the existence 

 of Lophobranchs, only a few SyngnatJms and Nerophis being 

 present in the more southern latitudes, to which they have 

 been carried by oceanic currents from their more congenial 

 home in the south. Scleroderms and Plectognaths are entirely 

 absent. 



The Gadoids are accompanied by Myxine, which parasiti- 

 cally thrives in them. 



II. The Nokthern Tempeeate Zone. 

 A. Shore Fishes of the Temperate North Atlantic. 



This part of the fauna may be subdivided into three 

 districts : — 



