10 
CANY ASS-BACK DUCK. 
linear-oblong, rather large, near the ridge, in an oblong depression covered 
with the soft membrane of the bill. Head rather large, compressed, convex 
above ; neck of moderate length, rather thick ; body full, depressed. Feet 
very short, strong, placed rather far behind ; tarsus very short, compressed, 
anteriorly with narrow scutella continuous with those of the middle toe, 
and having another series commencing half-way down and continuous with 
those of the outer toe: hind toe small, with an inner expanded margin; 
middle toe nearly double the length of the tarsus, outer a little shorter, all 
scutellate. Claws small, compressed, that of the first toe very small and 
curved. Plumage dense, firm, blended. Wings shortish, narrow, pointed, 
first and second quills longest ; inner secondaries elongated and tapering. 
Tail very short, rounded or cuneate, of fourteen or more feathers. (Eso- 
phagus rather wide, considerably dilated at the lower part of the neck ; 
stomach an extremely muscular, roundish gizzard ; intestine long and wide ; 
eoeca long. Trachea of the males with a transverse, bony, unsymmctrical 
dilatation at the inferior larynx. 
CANVASS- BACK DUCK. 
Fuligula valisneriana, Wils . 
PLATE CCCXCY; — Male and Female. 
The range of this celebrated Duck may be considered as limited on the 
one hand by the mouths of the Mississippi, and on the other by the Hudson 
or North river. Beyond the latter it is rarely seen at any season on our 
eastern coasts ; and this circumstance, conjoined with its being now and then 
observed on the upper waters of our Western Districts, and its breeding in 
great numbers on the borders of Bear river, which flows into the salt lake 
of Timpanajoz in Upper California, as well as in the marshes and along the 
banks of streams in many parts of the Rocky Mountains, induces me to 
believe that the individuals of this species, instead of proceeding along the 
-‘bores, pass overland towards their breeding grounds, however far northward 
they may be situated. According to Dr. Richardson, it breeds in all parts 
if the Fur Countries, from the 50th parallel to their most northern limits. 
