In this species, the number of feathers in the tail is eighteen, although it has been represented as sixteen. In form and proportions the Dusky Duck is very closely allied to the Mallard. The following account of the digestive and respiratory organs is obtained from the examination of an adult male. On the upper mandible are 43 lamellæ; on the lower, 85 in the upper, and 56 in the lower series. The tongue is 1-1/12 inch long, with the sides parallel and furnished with a double row of filaments, numerous small conical papillæ at the base, a median groove on the upper surface, and a thin rounded appendage, a twelfth and a half in length at the tip. The aperture of the glottis is 7-(1/2)/12 long, with very numerous minute papillæ behind. The œsophagus 12 inches long, of a uniform diameter of 4/12, until near the lower part of the neck, where it enlarges to 8/12, again contracts as it enters the thorax, ending in the proventriculus, which is 1-1/4 long, with numerous oblong glandules, about a twelfth in length. Gizzard obliquely elliptical, 2-1/4 inches across, 1-8/12 in length, its lateral muscles extremely large, the left 10/12 in thickness, the right 9/12; their tendons large and strong; the lower muscle moderately thick; the cuticular lining firm and rugous, the grinding surfaces nearly smooth. The intestine, which is 5 feet 7-1/2 inches long, is slender and nearly uniform in diameter, measuring 4/12 across in the duodenal portion, 3/12 in the rest of its extent; the rectum 3-1/2 inches long, dilated into a globular cloaca 1 inch in length, and of nearly the same diameter. The cæca are 6-1/4 long, (1-1/2)/12 in diameter for 2 inches of their length, enlarged to 3/12 in the rest of their extent, and terminating in an obtuse extremity. The trachea, moderately extended, is 10 inches long. Its lateral or contractor muscles are strong, and it is furnished with a pair of cleido-tracheals, and a pair of sterno-tracheals. The number of rings is 136, besides 12 united rings forming a large inferior larynx, which has a transversely oblong bony expansion, forming on the left side a bulging and rounded sac. There are 28 bronchial half rings on the right side, 26 on the left. BARTRAMIAN SANDPIPER. _TOTANUS BARTRAMIUS_, TEMM. PLATE CCCIII. MALE AND FEMALE. The Bartramian Sandpiper is the most truly terrestrial of its tribe with which I am acquainted. It is even more inclined, at all seasons, to keep away from the water, than the Kildeer Plover, which may often be seen wading in shallow pools, or searching along the sandy or muddy margins of the shores of the sea, or of fresh-water lakes and streams. Although not unfrequently met with in the vicinity of such places, it never ventures to wade into them; and yet the form and length of its legs and feet would naturally induce a person not acquainted with its habits to consider it as a wading bird.