EVOLUTION 55 



the fifty-fifty situation in the distribution of colour-phases of the fulmar 

 (as also of the bridling in the guillemot) is found at Bear Island, whose 

 position is between Low and High Arctic. However, the Pacific fulmar 

 appears to reverse the situation found in the Atlantic; the dark 

 fulmars are found in the warmer parts of the Pacific fulmar's range, 

 and the light fulmars progressively towards the colder parts, though 

 nowhere does this race of the fulmar breed in truly High Arctic waters. 

 The existence of these polymorphic forms of some birds constitutes 

 a problem of the greatest interest, which travellers and amateur 

 naturalists might well help to solve by collecting simple counts of 

 the relative proportions of easily recognisable forms. 



