420 
Natatokes.- 
-BIKDS.- 
-Anatidas. 
THE HOKNED SCREAMER {Palamedea cornuta ) — 
Plate 28, fig. 105— is nearly allied to the Jacanas. Its 
head is decorated with a singular long and slender 
horn, and its wings are armed each with two spurs. 
The toes, and especially the claws, are comparatively 
shorter than in the true Jacanas. This bird is about 
the size of a goose, and of a blackish colour, with a 
large red spot on each shoulder. It dwells in the 
marshes of South America, living in pairs, and utters 
loud cries which may be heard at a great distance. 
It is said to live chiefly upon leaves and seeds. 
THE CHAJA {Chauna chavaria), instead of the curi- 
ous horn of the Screamer, has on the back of the head 
a circle of feathers, which are capable of being raised 
or depressed at the pleasure of the bird. The Chaja 
is an inhabitant of Brazil and Paraguay; it feeds chiefly 
on vegetable matters, and is frequently kept with the 
domestic poultry, as it is said to drive away birds of 
prey. This bird is remarkable for the looseness of its 
skin, which appears to be separated from the subjacent 
muscles by a stratum of air-cells, and the skin crackles 
when the finger is pressed upon it. 
Order VIII.— NATATOEES. 
In the Natatorial or Swimming Birds we find in its 
highest state of development a character which, as 
already stated, occurs more or less amongst the mem- 
bers of the preceding order, namely, the union of the 
anterior toes by a web or membrane. In fact, in most 
of these birds the feet are completely palmated, the 
membranes e.xtending quite down to the extremities of 
the toes ; but this is not universally the case, for in 
some forms the toes are merely bordered with a wide 
membrane. The posterior toe is almost always small, 
more or less elevated on the back of the tarsus, and 
directed a little inwards; in a few species it attains 
a greater degree of development, and is then united by 
a membrane to the inner anterior toe. By the agency 
of these webbed feet the birds of this order are enabled 
to swim with great ease and rapidity, and most of them 
pass the greater portion of their existence upon the 
surface of the water, not a few also being able to dive 
and progress beneath the surface with astonishing faci- 
lity. The legs are usually rather short, and placed very 
far back towards the tail, a position which, coupled 
with the boat-like form of the body, greatly increases 
the natatorial power, but renders the gait of these 
birds upon dry land awkward and waddling in the 
extreme. In some forms, such as the Penguins and 
skeleton, the legs are so placed that the bird is com- 
pelled to hold itself quite upright when out of the 
water. 
The body, as already indicated, is of an elongated, 
boat-like form, admirably adapted for speedy motion 
through the water ; it is generally stout and bulky, 
and most frequently terminates in front in a rather 
elongated and very flexible neck. The plumage is 
dense, and exhibits a very thick under-coat of down ; 
the outer surface is kept conshintly greased by the 
birds, so that the water runs off it with great readi- 
ness. In other respects these birds exhibit many 
and important differences amongst themselves. In the 
development of the wings we find a far greater varia- 
tion than in any other order of birds, some species 
being endowed with enormous organs of flight, which 
suffice to support them in the air for the whole day 
without apparent fatigue ; whilst others have mere 
rudimentary pinions, quite unfitted for flight. The 
latter are the most thoroughly aquatic in their habits 
of the members of the order ; and between these two 
extremes we find every intermediate grade. The bill 
is also subject to great variations in size, form, and 
texture. 
As might be expected from the preceding state- 
ments, the habits of these birds vary greatly, and they 
form six well-defined families, presenting important 
dih'erences both in structure and mode of life. 
Family I.— ANATIDAl. 
The birds forming this family, of which our common 
Geese and Ducks are characteristic examples, are 
easily distinguished from all the rest of their order by 
the peculiar characters presetited by the bill. This 
organ is generally of a rather broad and flattened 
form, and furnished with a soft covering; and the 
edges of both mandibles exhibit a series of fine, tooth- 
like lamellse or plates. The office of these, which 
interlock when the mandibles are nearly closed, is to 
form a sort of strainer, by means of which the birds 
are enabled to separate small particles of food from llie 
water and mud in which they commonly seek their 
nourishment. The feet aie well developed, and the 
anterior toes are united by ample membranes ; the 
hinder toe is small, free, and raised more or less on 
the back of the tarsus. The wings are also tolerably 
large and powerful, enabling the birds, notwithstand- 
ing their bulky and rather heavy bodies, to fly with 
considerable ease and rapidity ; many of them are 
migratory in their habits, and perform long journeys 
to and from their breeding places. They are generally 
gregarious, and most of them frequent fresh waters, 
although they are often seen on the sea-shore in the 
winter season. Their food consists chiefly of worms, 
aquatic insects, and mollusca, which they obtain as 
above described by straining the mud and water 
through the fine lamellie of their bills. The species 
of this family are very numerous, and we can only 
refer to a few of the most interesting forms. 
THE FLAMINGO {Phcenicoptems ruler ) — Plate 29, 
fig. 109. — This singular bird undoubtedly presents the 
nearest approach in rnanj' respects to the preceding 
order, although its characters distinctly show that it 
belongs to the present family. It is supported upon 
