GREAT NORTHERN DIVER. 31 



into each other, and are ragged, the lower mandible separates into two 

 branches, which are united bj a thin elastic membrane, and are easily 

 movable horizontally or receding from each other, so as to form a 

 wider gap to facilitate the swallowing of large fish ; tongue bifid ; irides 

 dai'k blood red ; the head, and half of the length of the neck, are of a 

 deep black, with a green gloss, and purple reflections ; this is succeeded 

 by a band, consisting of interrupted white and black lateral stripes, 

 which encompasses the neck, and tapers to a point on its fore part, 

 without joining — this band measures about an inch and a half in its 

 widest part, and to appearance is not continuous on the back part of 

 the neck, being concealed by some thick, overhanging, black feathers, 

 but on separating the latter the band becomes visible : the feathers 

 which form these narrow stripes are wdiite, streaked down their centre 

 with black, and, what is a remarkable peculiarity, their webs project 

 above the common surface ; below this a broad band of dark glossy 

 green and violet, which is blended behind with the plumage of the back ; 

 the lower part of the neck, and the sides of the breast, are ribbed in 

 the same manner as the band above ; below ^the chin a few stripes of 

 the same ; the Avhole of the upper parts are of a deep black, slightly 

 glossed with green, and thickly spotted with white, in regular transverse 

 or semicircular rows, two spots on the end of each feather-- those on 

 the upper part of the back, shoulders, rump and tail coverts small and 

 roundish, those on the centre of the back, square and larger, those on 

 the scapulars are the largest, and of an oblong square shape ; the wing 

 feathers and tail are plain brown black, the latter composed of twenty 

 feathers ; the lower parts are pure white, a slight dusky line across the 

 vent ; the scapulars descend over the wing, when closed, and the belly 

 feathers ascend so as to meet them, by which means every part of the 

 wing is concealed, except towards the tip ; the outside of the legs and 

 feet is black, inside lead color ; the leg is four inches in length, and the 

 foot measures, along the exterior toe to the tip of its claw, four inches 

 and three-quarters ; both legs and feet are marked with five-sided 

 polygons. Weight of the specimen described eight pounds and a half. 



The adult male and female are alike in plumage. 



The young do not appear to obtain their perfect plumage until the 

 second or third year. One which I saw, and which was conjectured to 

 be a yearling, had its upper parts of a brown or mouse color ; a few 

 spots on the back and scapulars ; but none of those markings on the 

 neck, which distino-uish the fuU-jTroAvn male. Another had the whole 

 upper parts of a pale brown ; the plumage of part of the back and 

 scapulars tipped with pale ash ; the lower parts white, with a yellowish 

 tinge ; no bands on the neck, nor spots on the body. 



The conformation of the ribs and bones of this species is remarkable, 

 and merits particular examination. 



