“White’s conjecture of the purpose to which the serrated toe of the Nightjar is applied, namely, the better holding of the prey which it takes with its foot while flying, would have been more than rendered highly probable by an inspection of the foot of the Nyctibius. The inner front toe and the back toe are spread out by the great extension of the enveloping flesh of the phalanges, to such a breadth as to give the foot the character and form of a hand; while the movement of these prehensile organs is so adjusted that the back toe and the three front toes, pressed flat against one another, can enclose anything as effectually as the palms of the hands. The [claw of the] middle toe, which is serrated in the Caprimulgus, is simply dilated in the Nyctibius, a peculiarity also of the swallows. Whatever deficiency of prehension this may give it, when compared to the power of the serrated nail of the Caprimulgus, is amply compensated for in the Nyctibius, by the palm-like character of the foot, by the extraordinary expansion of the toes, and by the quantity of membrane connecting them together. All this would be a mere waste of power if it did not perform some function like that which White assigned to the foot of the Nightjar. “The feathers of the head, but especially those around the dilated gape, are of a peculiar structure. The covering of this part appears at first sight a mixture of hair and feathers, but upon close inspection, it is found to be composed of a loosely woven plumage, in which the shaft of each feather is prolonged into a pliant filament of great length. It is this texture which gives the character of intermingled hairs to the feathers around the mouth. This tendency in the shafts and in some of the webs also to terminate in filaments is very prevalent in the plumage of the Nyctibius, each of the feathers of the tail having this sort of termination.” The Potoo is a permanent inhabitant of Jamaica; it is common in the lowlands of the south side, and probably is generally distributed in the island: it is found also in Brazil, for I am quite satisfied that Mr. Gould’s _N. Pectoralis_ is not specifically distinct from ours. WHITE-HEADED POTOO.[11] _Nyctibius pallidus._—+Mihi.+ [11] Length 11 inches, expanse 22, rictus 1⁵⁄₈, beak from feathers to tip ⁵⁄₈, flexure 6, tail 3³⁄₄.