14 CANVASS-BACK DUCK.
of the liver;, proceeds backward beneath the kidneys, is convoluted in
Several large folds, and finally from above the stomach, passes in a direct
course to the anus. Its coats are thick, its inner surface villous,
and its diameter is considerable, beifflgïh'tine first part of thè duodenum
,"5, then for two feet from fa to T
4g, enlarged again to and so continuing
to the rectum, which is"6 inches long, ^ inch in diameter, and
ends in an enlargement or cloaca, about an, inch in diameter. , T h e
coeca, which commence at the distance of 6 inches from the anus, are 8
inches i o n g j i slender,: ^ in diameter for 3 inches, afterwards âbbut
with theitataemitysobtusei » Thes oesophagus and stomach contained
young .«hoots'of' •Zbstera marina; and in the latter were numerous fmrticles;
of qiuartz.; : • >
The trachea,' when ' moderately-»extênèed^ measures 10 iméhesfiin
length*: and is furnished ¡With-strong. lateral or, 'Contractor musôlesj a
pair of ¡oleido4racheal, ®nd a pair of »ciré' slender %ternoitraehealU' Its
diameter,at•theiNippef<ipariisi4J twelfths', ifc'^ÉàduallyieòntractS'ttSiS^
twelfths,- :e»largésito,'4}i twelfths,i^and a t the distancé of 7-J inches f rom
the upper extremity, forms a dilatation about, an ineh in' length, and
iiA-ix itó-.jgreatssttdiameter,'biiticsomposed of distinetfrings-,itheii contracts
to,s^j,;and.ends ini a bonyi and •membranous expansion, forming
on, thé, left iside ¡ah irregtdar thin'disk, :Ci)nveX:i towards the right, and
flattened towards the loft where it is membraimous.. The .expansions
of the..trachea are thus similar ¡to, those,; .of ¡the Ked-breastod :Merganuser,
bur .of,Jess extent,; the ringSr are jof equal breadth on both sidps,
but alternately overlap cadi other,,,ooMside .being;.partially concealed
b y th,e , corresponding sides of .thas:è,abo,Yeyand.iib,elQW- it, while, the
. other, stands exposed. The lower larHf.x,is,fo?Jned, ,oi ten/uftited rings,
> together with the ,bony ,and membranous'>expa^o,ni dgscìlibedf.i The
tracheal rings, rather bi;oad,and osseous;,,ayetMA; the Ji^lf-rings of the
bronchi about 16.,, <
i 15 )
DUSKY DUCK.
ANAS OBSCURA, G.mel.
PLATE 'Oteii: MAI* AHD Female.
This speciesj which is known in all parts of .the United States by
the name .of " Black Duck,'' extends its migrations from the Straits of
Belle Isle,'in the coast of Labrador, to the province of Texas, Strange
as the fact may appear, it breeds in both these countries, as well as in
many ¡of the intermediate districts. On the 10th of May 1833, I found
it breading along the marshy edges of inland pools-, near ,the. Bay.of
J'undy,' and, on Whitehead Island in the same: bay,, ¡saw several young
birds of the same, Bpeeiesi which, although'apparently not'more-than a
week old, were extremely active both on land and, in the water. On
the ,30th of April 1837, my son discovered a nest on Galveston Island,
in Texas. It was formed of,grass, and feathers, the/eggs eight in number,
lying on the former, surrounded with the down and some feathers
of the .bird, to the height of about three inches. The internal diameter
of the nest was about six inches, and its walls were .nearly three
in thickness. The, female was sitting, lint flew off in silence- as he approached.
The situation selected was a clump of tall slender grass, on
a rather sandy ridge, morb than a hundred yards from the nearest water,
but surrounded by partially'dried salt-marshes. On the salne
island, in the course of several Successive days, we Saw many of these
ducks, which, by their actions, shewed that they also had nests. I
may here state, my belief, that the Gadwall, Blue-winged Teal, Greenwinged
Teal, Mallard, American Widgeon, and Spoon-billed Duck, all
breed in that country, as I observed them there late in May, when they
were evidently paired. How far this fact may harmonize with the
theories of writers.respecting the migration of birds in general, is more
than I can at present , stop to consider. I have found the Black Duck
breeding on lakes near the Mississippi, as far up as its confluence with
the Ohio, as well as in Pennsylvania and New Jersey; and every one
acquainted with .its habits will ..tell you, that it rears its young in all
the.Eastern States intervening between that last ihentioned and the St