63 
the Province of Buenos Ayres. 
flimsy and slightly built structure. It contained three eggs 
of a bright pea-green colour^ measuring l'3x‘9 inch. I 
flushed one of the old birds from the nest. 
26. Nycticorax obscurus_, Bp.; Ibis_, 1877, p. 189. 
In November and December 1876 I found this bird com¬ 
mon in large flocks, chiefly immature birds, which do not 
attain their full plumage till more than a year old. 
27. Phimosus infuscatus (Licht.) ; Nomencl. p. 127. 
Last summer I saw some eggs of this bird, obtained, shortly 
before Christmas, about two hundred miles to the south of 
Buenos Ayres. They are of a bright azure-blue colour and 
very handsome. A friend who has taken the nests tells me 
they are found on a dry spot close to a lagoon, and com¬ 
posed of a few pieces of grass in a slight hollow. Pour is 
the full complement of eggs. 
15th April 1877. Common in this neighbourhood in large 
flocks. Birds of the year have much naked skin on the fore¬ 
head, and many brown feathers on the head. 
28. Chauna chavaria, Linn, j Ibis, 1877, p. 190. 
Though apparently such an awkward unwieldy bird, the 
Screamer can, and frequently does, rise to such a height 
as to appear a mere speck in the sky, and I have often 
watched two or three birds gracefully circling round each 
other like Eagles for half an hour at a time. They are 
enabled to do this owing to there being a considerable quan¬ 
tity of air, which is retained in small cells, between the outer 
skin and the lining membrane of the body, especially on the 
chest and stomach, and less visibly on the sides. On the 
11th Pebruary 1877 I shot a young bird in downy state, 
presumably about ten days old. Head light rust-colour, 
neck pale grey, back pale chocolate; wings very small and, 
with the breast and stomach, grey; iris wood-brown; feet 
brick-red. 
— 29. Dendrocygna eulva (Gm.); Nomencl. p. 129. 
Common at Alvear in September and at Punta Lara in De¬ 
cember, congregating in enormous flocks. Whilst on the 
