These are the peculiarities of structure which ibelcuïgl-tê^tlic
tube’and th^ BteruuBai_The brohebimj. aier^very'short; but
the flexible part intervening^ between- the; bqtfeof divar-iqaitibfi
and-the bronchial rings is considerable,, producing an effect- to
be“ hereafter'noticed.. This elongated, flexiM^bndjiiilcate
portion, being defended on each outer side Ibf^a distinct mem*
brane, attached, to the whole edge? 4f_thë' bone of .davaricati?0ny
and to a, slender semicircular bone on each side,-by which it
is supported. &
: T h e muscles ot voice with which this bird is provided, pass
down, as. üstial; one ofi • each* side .of the trachea, till jthe tube
is aboitt to enter the cavity in the keel*, they then quit that
partsof the tube to be attached to the ascénding, portion of
the curve, which they follow, ultimately dividing into two
slips, one of which inserted, upon the surface of the bone of
divarication governs the length of the- preceding flexible portion
of the tu b e ; thé other slip passes off downwards to be
attached to the inner surface of the breast-bone, anterior to
the first rib. The course of the muscle on one side may be
traced in the first anatomical figure.
$HThe vignette at the end of* this subject represents a front
of ra portion of tfye*. body* of this species of Swan, with
the''anterior part of the descending windpipe turned aside to
show the inner ascending part* of it, the muscles of voice, and
the tendinous fascia stretched across from . one branch of the
forked bone or merrythought over to'the other, by which both
portions are supported.
Dissection, which proved the distinction between the Hooper1
and Bewick’s, Swan, has also proved that the two Wild
Swans of North America arc peculiar to that country, and
distinct from the two European Swans. The largest of the
North America® -Swans, still larger than our Hooper, is
called Cygnus buccinator*, or the Hunter’s Swan, by Dr.
Richardson, in his Fauna Boreali-Americana, where the measurements
and other particulars of its history will be found;
and I am indebted to the liberality "of Dr. Richardson for a
t specimen of the very singular organs of voice and the sternum
of this species, which will be found described and figured in
the seventeenth volume of the Transactions of the Linncan
Society.
The second species ofiNorth American Swan was described
by Dr. Sharpless, in the fifth velurtie of the American Jour-
nal of Science and Arts, under the name of Cygnus Ameri-
canus; it has also been described more recently by Mr.
Audubon, in the fifth volume of his Ornithological Biography.
Iihave been presented by both these gentlemen with the
organ of voice and the sternum from several examples of this
second species of American Swan, which, however, in some
respects, internally as well as externally, resembling our Bewick’s
Swan, is said to attain a size and weight almost equal
to those of our Hooper; the whole length is recorded as