The Prince Maximilian’s specimens of this bird were obtained on Maria’s river, one of the tributaries of the Upper Missouri, in the northern part of the possessions of the United States in Western America, and much farther north than it has been observed by either of the late naturalists. It probably inhabits a very extensive district, the limits of which cannot at present be conjectured. The figure in the present plate is that of the adult male, and is about two-thirds of the natural size. DESCRIPTION AND TECHNICAL OBSERVATIONS. Genus Gymnokitta. De Wied in Bonap. Consp. Av., p. 382. (1850.) General form, rather short, robust; bill, straight, wide at base, somewhat rounded and flattened at the point, ridge of the under mandible (or gonys) very distinctly ascending; wings, rather long, first quill very short, fourth, longest, but only slightly longer than the third and fifth; tail, moderate, containing twelve feathers; legs and feet, strong. Gymnokitta cyanocephala. (De Wied). Gymnorhinus cyanocephalus. De Wied, Travels in North America (1839, Coblenz). Cyanocorax Cassinii. McCall, Proc. Acad. Philada., V. p. 216. (1851.) Form. Bill, straight, wide at base, blunt and rounded, and somewhat flattened towards the point; wings, rather long, secondaries, broad and mostly obtuse at their ends; tail, moderate, tarsi rather long, moderately robust, and with the toes distinctly scaled; claws, curved, rather strong and sharp. Dimensions. Total length (of skin), about 10 inches; wing, 6; tail, 4½; bill, from gape, 1½ inches. Colors. _Adult._—Throat, white, tinged with bluish running into stripes on the neck before. Entire other plumage, above and below, ashy-blue, much darker and clearer on the head, palest on the abdomen, tibiæ and under wing coverts. Cheeks and frontal feathers, pale ultramarine; bill and claws dark; irides, light-brown—sexes alike. Hab. New Mexico, Nebraska. Spec. in Mus. Acad., Philada., and Nat. Mus., Washington city. Obs. This species does not resemble any other in such degree as to readily lead to confusion, and as yet stands alone in its genus. The bird described by Col. McCall, as above, and to which he did us the honor to apply our name, he has since ascertained to be the present species, of which, at the time of the publication of his description, no specimen was exhibited in the nearly complete collection of Jays in the museum of the Philadelphia Academy, nor had it ever been mentioned by any American ornithologist. He observed it in the vicinity of Santa Fé, in considerable numbers.