in the Egyptian Tantalus. 7 501 
the ducks, having only a trifling enlargement of that organ and 
of the bronchi. E 
The Cracide and Capricalee (Urogallus) exhibit also ma- 
nifestations of similar conformation, as well as an individual of 
the Cassican family, described by M. Lesson in his ** Manuel 
d'Ornithologie," under the title Phonygama Keraudrenii, and 
probably in other birds whose larynges and tracheæ have not 
as yet fallen under my notice. 
The very remarkable circumstance of the trachee in many 
birds, especially those of the order Natatores, being ossified and 
composed of various pieces, and each ring being entire (not as 
in man and mammalia, having a muscular membrane occupy- 
ing the posterior third part of the canal), which possibly can only 
be accounted for from the apparent necessity of the air being 
required to remain in the body of the animal, rarefied in readi- 
ness for the purpose of raising itself, whenever it may be induced 
to wing its flight through the atmosphere ; and assuredly aquatic 
birds must be rendered very buoyant in consequence when 
swimming. 
The bodies of the pelican (Onocrotalus), gannet (Sula), and 
chaja (Palamedea Chavaria) may be inflated almost like a blad- 
der between the skin and muscles; so also, but partially, that 
of the powting pigeon, the adjutant, marabou, and tachypetes, 
but particularly the emeu, whose trachea, somewhat below the 
middle of the neck, being there deficient in cartilaginous rings, 
is formed into a membranous sac, which can be distended at 
pleasure : and everybody has seen the male turkey, in the pride 
of dominion, enlarge its breast and even menace the spectator ; 
faculties clearly tending to accelerate progression when required. 
With few exceptions, birds, having a crop, are not furnished 
with inflexions, or obvious deviations from the apparent ordi- 
nary 
