410 



NATATORES. COLYMBUS. 



DIVER. 



Young. 

 First year. 



Second 

 year. 



Third 

 year. 



but becoming small and nearly round upon the lower 

 part of the back and rump. Flanks and sides black, 

 spotted with white. The rest of the under plumage 

 white ; the long axillary feathers the same, with a black 

 stripe down their centres. Tail short and rounded, 

 black, consisting of twenty feathers. Legs greyish- 

 black, paler on the inside. Irides reddish-brown. 



The young of the year (Colyrnbus Immer, Auctor.) differ 

 strongly from the adults, as follows : Head, and back 

 part of the neck, deep-grey, tinged with clove-brown. 

 Fore part of the neck, and the under plumage, pure 

 white, except the flanks, which are clove-brown. Up- 

 per plumage deep clove-brown, the feathers being mar- 

 gined with ash-grey. Upper mandible of the bill deep- 

 grey, the under one much paler. 



After the second general moult, a darkish band appears 

 on the middle of the neck, and the upper plumage be- 

 comes darker, losing the pale grey edges that distinguish 

 the young of the year, and a few white spots begin to 

 shew themselves. The succeeding moult developes still 

 more the bar and neck collar ; and the head and neck 

 become darker, or of a blackish-green, speckled upon 

 the chin and throat with white. The upper plumage 

 also acquires its glossy black lustre, with the accompany- 

 ing quadrangular white spots. In the next change, or 

 when the bird has passed its third year, the plumage is 

 perfected. 



