80 ALCIDiE. 



does not differ from the Common Guillemot. The eggs are 

 as a rule somewhat thicker and blunter, and in the green 

 varieties the colour is perhaps a trifle brighter. 



A specimen of the bird brought from Iceland by Mr. 

 Proctor agrees exactly with Sir Edward Sabine's description 

 of this species in its summer plumage. The beak is black, 

 the posterior half of the marginal portion of the upper man- 

 dible nearly white, extending from the corner of the mouth 

 to the point where the feathers project on the bill, and form- 

 ing a very characteristic mark ; the irides dark brown ; throat 

 sooty-brown, as in the Razor-bill ; head, neck behind, back, 

 wings, and tail black, with a greenish gloss ; secondaries 

 tipped with white, forming a bar across the wing ; belly, and 

 all beneath, pure white, running up to a point on the front 

 of the neck ; in the Common Guillemot the white colour 

 ends here in the form of a rounded arch ; legs and toes 

 yellowish-olive on the upper parts, dark brown below ; mem- 

 branes brownish-black. The whole length is eighteen inches. 

 From the wrist to the end of the longest quill-feather eight 

 inches and a quarter. The sexes are alike in plumage, but 

 the female is rather smaller than the male. 



This species undergoes the same changes of plumage 

 from season as the U. troile. Sabine remarks that speci- 

 mens killed early in June had the throat and neck white, 

 unmixed with black ; towards the end of June the change 

 was in progress, and by the second week in July, as many 

 were found in perfect summer plumage, with black throats 

 and necks, as were still in change. Adult birds lose their 

 dark throat at the autumn moult. 



