26 RED-THROATED DIVER. 



Bill bluish-black. Iris deep bright red. Feet brownish-black, the 

 anterior edge of the tarsus, the upper surface of the toes, the claws, and 

 part of the webs, pale livid flesh-colour. Fore part and sides of the head, 

 throat, and sides of the neck, of a fine bluish-grey ; fore part of the neck 

 rich brownish-red ; hind part of the head and hind neck longitudinally 

 streaked with greenish-black and pure white, each feather black in the 

 middle, with the sides white, the colours disposed in lines. The upper 

 surface brownish-black, tinged with green, more or less mottled with 

 white according to age, excepting the primary quills and the tail-feathers, 

 the latter of which are merely paler at the end. The whole under sur- 

 face pure white, excepting the feathers on the sides under the wings, 

 some of those about the vent, and the lower tail-coverts, which are grey- 

 ish-brown, with white margins and tips. 



Length to end of tail 25h inches, to end of claws 27, extent of wings 

 43^^2 ; bill 2/5, gape Sf ; tarsus 3, fourth toe and claw 3| ; wing from 

 flexure 11 1, tail 3. Weight 4 lb. 



Adult Female in summer. Plate CCII. Fig. 3. 



The female is precisely similar to the male in form and colouring, but 

 is considerably smaller. 



Length to end of tail 25 inches, to end of claws SSj'^ ; extent of wings 

 43. Weight 3 lb. 



Male in winter immature. Plate CCIL Fig. 2. 



In this state the principal differences are the following : — The fore 

 part of the neck, instead of being of a uniform rich brownish-red, is mere- 

 ly mottled with that colour ; all the feathers of the upper surface have 

 each two white spots towards the end ; the tail-feathers are edged and ter- 

 minated with white ; the colouring in general is somewhat less pure and 

 deep, and the bill is of a much paler tint. 



Young bird unfledged. Plate CCII. Fig. 4. 



The young are at first covered with a dense elastic down of a greyish 

 black colour, tinged with brown. The bill is bluish-black, its basal edges 

 yellow ; the iris reddish-brown. 



