PALMIPEDES. 261 
Tropic-birds]. On land, where they seldom resort except to breed, they perch upon trees. [They are 
closely related by affinity to the Gannets.] 
Several species are known, with white plumage, more or less varied with black, [and tinged in some with roseate,] 
which do not exceed the size of a Pigeon. 
The family of 
Lamellirostres 
Is distinguished by a thick bill, invested with a soft skin rather than with true horn, [the 
fact being, that the corneous portion is restricted to the nail-like extremity, the rest corre- 
sponding to what is known as the cere] : its edges supplied either with laminae, or small 
teeth, [which are modifications of each other] : the tongue large and fleshy, with a dentelated 
border. Their wings are of moderate length. They live more in fresh winters than in the 
sea : and, in the greater number, the trachea of the male is dilated near its bifurcation into 
capsules of various form. Their gizzard is large, very muscular, and the coeca [generally] 
long. [These birds lay numerous spotless eggs, and the young follow tlieir parent as soon 
as hatched.] 
The great genus of 
The Ducks {Anas, Lin.) — 
Comprehends those Palmipedes which have a large and broad bill, the edges of which are beset with 
salient laminae jjlaced transversely, and the purport of which appears to be for straining off the water 
when the bird has seized its prey. They divide into three subgenera, the limits of which, however, 
I are not very precise. 
; The Swans {Cygnus, Meyer) — ■ 
Have the bill of equal breadth throughout, and higher than wide at the base ; the nostrils placed about 
midway: and the neck exceedingly elongated, [possessing twenty-three vertebrae*]. They are the 
largest birds of this genus, and feed chiefly on the seeds and roots of aquatic plants, [togetlier with the 
grass which grows near the brink of water]. Their intestines, and coeca more especially, are accord- 
ingly very long. Their trachea has no inflation or labyrinth. 
[Swans are essentially modified Geese, and like the latter are exclusively vegetable feeders, with 
similar plumage in both sexes, which is moulted once only in the year, and undergoes no seasonal va- 
riation of colour. They attack with the same hissing note, strike similarly with their wings, and the 
male guards the female during incubation, and accompanies her while followed by her brood. They 
fall into two subdivisions. 
In the first, the trachea, after describing a slight curve towards the sternal ridge, proceeds to the 
lungs without entering any cavity in the bone. When swimming, they often erect the tertial plumes 
! of the wing, in an elegant manner. Three of the four species have a fleshy caruncle over the base of j 
} the upper mandible, beneath which the bone is protuberant. j 
The Mute Swan {Anas olor, Gmelin), or common domesticated species, the adults of which are wholly pure I 
white, with a reddish bill, surmounted by a black protuberance, and leaden-black feet : young, grey, with the bill 
lead-coloured. The wild breed {C. immutabilis, Yarrell) is rather smaller, with the rostral protuberance less 
developed in the few specimens examined : there is also a semi-albino domestic race, with feet whitish, or par- 
tially so, and reported to have white cygnets, which is termed the Polish Swan by the dealers ; it varies in size, 
some attaining the largest dimensions of the ordinary tame breed. We are satisfied, from anatomical examina- 
i tion, that these are all specifically the same. The wild race is rarely met with in Britain. These birds do not 
I appear to breed before the third year. 
I The Black Swan {A. atrata, Latham ; A. plutonia, Shaw). — Less than the preceding, and not so elegant in its 
conformation, with its tertials curled upwards : colour black, with the exception of its white primaries, and the 
bill and naked skin at its base, which are red. It is common in New Holland, and propagates readily twice a 
year, or oftener, when brought to Europe. 
The Black-necked Swan (C. nigricolUs). — White, with black neck and tips of the primaries ; the sides of the 
head white, and bill and feet orange, the former having a black protuberance. Common in South America. 
i|j Tlie smallest of all, or Duck-billed Swan (C. anatoides, King.), is also from South America, inhabiting towards the 
I Straits of Magellan. Colour pure white, with black tips to the primaries, and bill and feet orange : the former 
1 having no basal protuberance. With the exception, therefore, of the common mute species, this division pertains 
to the southern hemisphere. 
The rest have the trachea elongated as in the Cranes, and similarly entering a cavity in the sternal 
* We have found this number in four species, viz., C. olor, atratus, musicus, and Bewickii. — Ed. 
