The remaining member of this genus is the beautiful Black-necked Swan (C. Melanocoryphus) of southern South America. It is about forty-eight inches in length and is pure white, except the head and upper two thirds of the neck, which are black with a velvet gloss, and there is also a narrow white stripe surrounding the eye and extending backward to the nape. The base of the bill and the knob are bright red, the remainder of the bill bluish. Mr. Hudson tells us that this species is very abundant on the pampas of Buenos Ayres and Patagonia, where it is seen about the watercourses in small flocks or occasionally in hundreds. They breed in July, the nest being ” always placed among thick rushes growing in deep water. It is built up from the bottom of the swamp, sometimes through four or five feet of water, and rises a foot and a half above the surface. The top of the nest measures about two feet across, with a slight hollow for the eggs,” which are three to five in number and cream-colored, with a smooth, glossy shell.