Dr. Cornelius is a chimpanzee archaeologist and historian who appears in the original novel of Planet of the Apes (La Planète des singes), and also the first three installments of the classic movie series of the same name, from the 1960s and 1970s. He was portrayed by Roddy McDowall and, in the second movie, by David Watson.
who plays cornelius in planet of the apes
Roddy McDowall David Watson