The trachea, 10-1/2 inches long, has at first a diameter of 4 twelfths, dilates gradually to 8 twelfths, then contracts to 4 twelfths, enlarges a second time to 7 twelfths, and gradually contracts to 3 twelfths. In this space the rings, 146, are strong, broad, and osseous. At its lower part is an enormous dilatation composed of numerous united rings, bulging irregularly on the right side and behind, and on the left expanded into a case having two large spaces filled by membrane; the greatest diameter of this tympanum is 2 inches and 2 twelfths. The bronchi come off at the distance of nearly an inch from each other, and are short, but wide, with about 25 half-rings. The lateral or contractor muscles are very strong, give off a pair of cleido-tracheals from the second enlargement, and at the commencement of the labyrinth the sterno-tracheals, which are also very large; but there are no other inferior laryngeal muscles. The intestine of a male in the first winter is 6 feet 8 inches long, its greatest diameter half an inch, wider towards the rectum than at the upper part, where the diameter is 4 twelfths. Rectum 4-1/2 inches long, exclusive of the cloaca. Cœca 2-1/4 inches. Contents of stomach, remains of fishes and a great quantity of quartz fragments. An adult Female. Œsophagus 10-1/2 inches long; stomach 2 inches long; intestine 5 feet 3 inches; rectum 4-1/2; cœca 2-2/12. The trachea 9 inches long, of uniform diameter, 4 twelfths, with a very slight dilatation toward the lower part, and at the lower larynx contracted to 3 twelfths; the last ring is very large, laterally dilated, but symmetrical; the bronchi come off at the distance of 5 twelfths from each other, and are composed of 25 rings. The tracheal rings 150. With respect to their digestive organs, the Mergansers are perhaps more allied to the Divers than to the Ducks. In this, as in other respects, they seem to be placed on the limits of the two families. PIED DUCK. _FULIGULA LABRADORA_, GMEL. PLATE CCCXXXII. MALE AND FEMALE.