The Dryas Monkey (Cercopithecus dryas), also known as Salonga Monkey or Ntolu, is a little-known species of guenon found only in the Congo Basin, restricted to the left bank of the Congo River. It is now established that the animals previously classified as Cercopithecus salongo (common name Zaire Diana Monkey) were in fact Dryas Monkeys. Some older sources treat the Dryas Monkey as a subspecies of the Diana Monkey and classify it as Cercopithecus diana dryas,...