In a male, the roof of the mouth is deeply concave, with a prominent median ridge, and oblique grooves toward the end. The tongue is 1 inch 10 twelfths long, fleshy, with a deep longitudinal groove, two lateral series of filaments, and a thin broadly rounded tip, as in other ducks. The œsophagus, _a_, _b_, is 10-1/2 inches long, 5 twelfths in diameter for about four inches, then enlarged to 10 twelfths, and again contracted as it enters the thorax. The proventriculus, _b b_, is 1 inch and two twelfths long, its greatest diameter 8 twelfths. The stomach, _c d e_, is a very large and powerful gizzard, of an elliptical form, compressed, 1 inch and 9 twelfths long, 2 inches in its greatest breadth, or in the direction of the lateral muscles, of which the right, _c_, is 10 twelfths thick, the left, _d_, 9 twelfths. The epithelium is thick and rugous; much thickened and forming two roundish, flat or slightly concave grinding surfaces, opposite the muscles. The intestine, _e f g_, is 6 feet 10 inches long, wide, its diameter for 2 feet being 4-1/2 twelfths, towards the rectum enlarging to 6 twelfths. It forms first a very long duodenal curve, _c e f g_, and is then convoluted or coiled in numerous folds. The rectum is 5-1/4 inches long; the cœca 11 inches, their greatest diameter 6 twelfths, for 2 inches at the commencement 2 twelfths, towards the end 2-1/2 twelfths, their extremity rounded. [Illustration] The trachea, _h_, is 7-1/2 inches long; its diameter at the upper part 4 twelfths, gradually diminishing to 3-1/2 twelfths; it then enlarges to 5 twelfths, and contracts to 3-1/2 twelfths at the commencement of the dilatation of the inferior larynx, which is extremely similar to that of the Widgeon, but larger; there being an enlargement, _i_, formed by a number of the lower rings united, and to the left side a rounded bony tympanum _j_; the greatest transverse diameter of this part, from _i_ to _j_, is 1 inch 1 twelfth. The bronchi, _k k_, are of moderate size, covered with a dense layer of adipose matter. LEAST WATER RAIL. _RALLUS JAMAICENSIS_, GMEL. PLATE CCCXLIX. MALE AND YOUNG. My knowledge of this pretty little species is altogether derived from TITIAN PEALE, Esq., of Philadelphia, by whom, in October 1836, I was favoured with the following letter:— “I herewith send you the ‘Little Rail’ of which we were speaking yesterday, and the letter of Dr ROWAN which relates to it. The young died soon after I received them, but the old one lived with me until the 26th of July (four days after its capture), evincing considerable anxiety for the young, as long as they lived. Both young and old partook sparingly of Indian meal and water, or bread and water, and soon became quite at home, and probably might have been domesticated, had they been properly accommodated.