1. PODICIPES. 509 



mixed with silver}' white, especially towards the middle of the 

 ]jody ; primaries brown ; outermost secondaries brown, white on 

 the basal two-thirds of the inner web ; median and inner secondaries 

 with the inner web and tip and often (in old birds ?) the basal part 

 of the outer web white ; under wing-coverts pure white ; tutt of 

 hairy feathers forming the vestigial tail mostly black. Iris reddish 

 brown ; upper and lower mandible blackish, pale horn at the tip ; 

 naked skin round the gape and at the base of the lower mandible 

 yellow, in front of the eye blackish ; feet slate-grey ; outer side 

 of metatarsus and soles blackish. Total length about 9-5 inches, 

 culmen from feathers on forehead 0-6.5-0'8, wing 3'7-4, tarsus 

 l-3-l"4, outer toe and claw 1-8-1-9. 



Adult ill non-hreeding plumage. Forehead, crown, back of the 

 neck, and upper parts dark brown, very slightly glossed ; cheeks, 

 sides of the head and neck, base of fore-neck and chest dull brownish 

 buff, rather darker below the eye and on the ear-coverts ; chin and 

 throat pure white ; rest of underparts silvery white, shading into 

 brownish buff on the sides and fianks, and dark smoky-grey on the 

 lower belly ; plumage otherwise similar to the adult in breeding- 

 plumage. Basal half of the cutting-edge of the upper mandible and 

 greater part of the lower mandible yellowish. 



Nestling in down. General colour black ; breast and belly pure 

 white; forehead shining silvery grey ; the head, neck, and back with 

 longitudinal stripes of pale rufous, inclining to whitish behind the 

 eye and on the throat. 



As the bird becomes older the down on the head and neck becomes 

 beautifully patterned with brownish-black and silvery-white markings 

 and stripes, and at the same time the upper parts change to dark 

 brown with longitudinal stripes of dull rufous white. 



A half-groAvn bird obtained on the 2.5th of September resembles 

 the adult in winter plumage, but the black-and-Avhite pattern on 

 the cheeks and sides of the head are still conspicuous ; these 

 markings, however, gradually disappear, and by the mouth of January 

 the j'oung bird is not to be distinguished from its parent in winter 

 plumage ; the bill being equally developed and the plumage abso- 

 lutely similar. 



In most immature birds the brown on the outer webs of the inner 

 secondaries extends beyond the shaft on to the inner web. 



In the beginning of February the bill becomes black like that 

 of the bird in summer plumage ; at the same time the chestnut 

 feathers on the sides of the head and neck begin to make their 

 appearance, while apparently simultaneously some of the white 

 winter feathers of the throat become tinged with pale chestnut. 



By April the summer plumage of the head and neck is nearly 

 complete, though a certain number of pale feathers are still inter- 

 mixed with the plumage of the throat, sides of the head and neck. 

 At this period the black feathers of the chest and underparts begin 

 to make their ap earance. These are mostly the result of moult, 

 and are complete by the beginning of if ay, when the bird has 

 assumed the full breeding-plumage. 



