WHITE MERGANSER. 409 



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 band 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, excepting the tips of both, deep black. The quills are also 



Vol. VI. 5G 



