° 1918 J Dwight, A New Species of Loon. 199 



The Green-throated or Siberian Loon may prove to be only 

 subspecifically separable from its purple-throated relative, the 

 Black-throated or Arctic Loon, but there seems to be a distinct 

 qualitative difference between the green and the purple of the 

 respective throats, that merits specific recognition. Except for 

 this striking difference viridigularis and arctica are much alike 

 in coloration, although the former has wider white bars on the 

 scapulars and the upper parts are green-tinged rather than purplish 

 as in arctica; the former too is, perhaps, a little larger in all dimen- 

 sions. Specimens of arctica no matter how they are held to the 

 light show a velvety purple on the throat that looks black in a 

 poor light, while those of viridigularis are wholly green when held 

 between the observer and the light and they develop a tinge of 

 brownish-purple only if held in the opposite direction. I have 

 seen one or two specimens that are somewhat intermediate between 

 the two species but there is a gap that remains to be bridged. 



We have then Gavia arctica arctica the northern European bird 

 with Gavia arctica suschkini, a southern race in Turkestan and Gavia 

 arctica pacifica its representative in Arctic North America, — all 

 three purple-throated, and Gavia viridigularis a green-throated 

 species that occupies a range in eastern Siberia. Buturlin as 

 quoted may have mistaken viridigularis for pacifica which would 

 account for his " arcticus" and " pacificus" breeding side by side, 

 but however this may be, we have to reckon with a green-throated 

 bird that hitherto has been without a name. 



