the native name of a group of tropical American monkeys nearly allied to those known as uakaris (see Uakari), with which they agree in the forward inclination of the lower incisor teeth, the depth of the hinder part of the lower jaw, and the non-prehensile tail. The;sakis, which form the genus Pithecia, are specially characterized by their long and generally bushy tails, distinct whiskers and beard, and the usually elongated hair on the crown of the head, which may either radiate from a point in the centre, or be divided by a median parting. They are very delicate animals, difficult to keep in confinement, and in that state exhibiting a gentle disposition, and being normally silent (see Primates).