THE EUROPEAN SEAS. 193 



served by M. Valenciennes, that this community 

 has reference in some cases to fishes which are not 

 migratory, such as Pimelepterus incisor ; and that 

 the form and nature of a coast-line influence the 

 distribution of fishes far more than temperature 

 dependent on latitude. The migratory movements 

 of fishes, like those of birds, are made in obedience 

 to given wants and instincts, and are conducted, 

 like the voyages of the early navigators, not across 

 the trackless depths of the ocean, but along lines of 

 coast. « 



It is somewhat remarkable, that so far as our 

 present knowledge goes, some of the American forms 

 of fishes found about the Canaries do not reach the 

 African coast, a consideration which, in conjunction 

 with others we shall have to notice, lends support 

 to the view already put forth (p. 1 1 3), that the west- 

 ern boundary of the " old world " was once placed 

 so much farther westward, as to reach these At- 

 lantic islands. The occurrence of common forms, 

 more particularly of the species which have been 

 cited, can only be explained by the coasts of the 

 two sides of the Atlantic having once been placed 

 much nearer to one another along some line south 

 of our Lusitanian province. 



Of the fishes of the Canaries, seventy are found 

 in the Mediterranean ; of these, many are also 

 West African forms. There are some others, such as 

 Pristopoma ronchus, Sargus cervinus, Chrysophrys 

 cceruleosticta, and Lichia glaycos, which are also West 



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