120 
WHITE MERGANSER. 
Exceedingly rare in America, one specimen only having been procured at 
New Orleans. 
Adult Male. 
Bill rather shorter than the head, straight, rather slender, a little higher 
than broad at the base, tapering, somewhat cylindrical toward the end. 
Upper mandible with the dorsal outline sloping gently and slightly concave 
to the middle, then straight, at the tip decurved, the ridge rather broad and 
flat at the base, then convex, the sides sloping at the base, convex toward 
the end, the edges serrate beneath, with about forty slightly reversed, com- 
pressed, tapering, tooth-like lamellae, the unguis elliptical, much curved. 
Nasal groove oblong, sub-basal, filled by a soft membrane ; nostrils oblong, 
sub-medial, direct, pervious. Lower mandible with the angle very narrow 
and extended to the obovate, very convex unguis, the sides rounded, with a 
long groove, the edges with about sixty perpendicular sharp lamellae. 
Head of moderate size, oblong, compressed. Neck of moderate length. 
Body full and depressed. Feet placed far behind, extremely short ; tibia 
bare for a quarter of an inch ; tarsus extremely short, much compressed, 
anteriorly covered with a series of very small scutella, and another row on 
the lower half externally, the sides reticulate. Hind toe very small, with 
an inferior free membrane ; anterior toes double the length of the tarsus ; 
the second shorter than the fourth, which is nearly as long as the third ; 
all connected by reticulated webs, of which the outer is deeply emarginate. 
Claws short, considerably curved, compressed, acute, that of the middle toe 
with a thin inner edge. 
Plumage full, soft, and blended ; feathers of the head and upper part of 
the hind neck very slender, and elongated along the median line into a 
narrow decurved crest ; those of the shoulders obovate and abrupt, of the 
rest of the upper parts ovate, of the lower elliptical. Wings very short, 
narrow, curved, and pointed ; primaries narrow, tapering, the first scarcely 
longer than the second, the rest rapidly graduated ; secondaries short, narrow, 
rounded, the inner tapering to an obtuse point. Tail short, graduated, of 
sixteen rather narrow, tapering feathers. 
Bill dark greyish-blue. Iris bright red. Feet livid blue, claws dusky. 
The general colour of the plumage is pure white ; a short hand on each side 
of the hind neck bordering the crest, duck-green ; a broad patch on the lore 
and below the eye, a narrow band across the lower part of the hind neck, 
formed by single bars near the tips of the feathers, the middle of the back 
in its whole length, a short transverse bar under the fore edge of the wing, 
the anterior margin of that organ to beyond the carpal joint, the outer edges 
of the scapulars, the primary coverts, the secondary coverts, and the outer 
secondary quills, exeepting the tips of both, deep black. The quills are also 
