178 ON THE CLASSIFICATION OP BIRDS. 
feet sufficiently broad to assist them in swimming. The 
immediate affinities of these curious birds, however, are 
very doubtful. 
(200.) The Rallid^ comprise the rails and water- 
hens, and constitute a very natural and well-marked family 
in the order of waders. They have been designated by 
these familiar names, from their peculiarly harsh notes, 
and by assuming much of the appearance of gallinaceous 
or rasorial birds ; another proof that the true analogies of 
nature are often perceived by the vulgar, although passed 
over by the scientific. The most prominent differences 
in their structure, when compared with the foregoing 
families, is the great sisfe of the leg, and the length of 
tlie toes, particularly the hinder one ; the body is very 
thin, and unusually flattened ; a structure particularly 
adapted to the habits of rails, since they live for the 
most part in the thick and entangled recesses of those 
reeds and aquatic vegetables which clothe the sides of 
rivers and morasses. They are, for the most part 
solitary and timid birds, hiding themselves at the least 
approach of danger, but quitting their semi-aquatic 
retreats in the morning and evening, to feed in more 
open spots : their flight, from the shortness of the wings, 
is very feeble, but they run with swiftness ; and, by the 
peculiarly compressed fonn of their body, are able 
to make their way through dense masses of reeds and 
high grass with so much facility as to escape, even 
after being desperately wounded. The flesh of all 
these birds is delicate ; and, from living chiefly upon 
aquatic seeds and vegetable aliment, they may be con- 
sidered as aquatic Gallinacea. 
(201.) The following are among the most obvious 
genera or subgenera which enter into the present group. 
Of these the jacanas (JParra) are the most singular: they 
arc distinguished by toes of such remarkable length, 
that, by covering an enormous circumference, these birds 
can walk upon aquatic plants floating on the surface 
of the water, with as much ease and security as if they 
made their way over hard ground. Most of the species 
