Primates, 19th-century artwork. Shown here are an orangutan (upper left), a lotong mother and baby (upper right), a proboscis monkey (lower left), and a baboon (lower right). These 19th-century Latin names are archaic. Orangutans are now classified in the genus Pongo, the proboscis monkey in the genus Nasalis, and baboons in the genus Papio. Some monkeys from Java are known as lotongs. Artwork from 'Encyclopaedia Metropolitana', an encyclopedia published in London between 1817 and 1845. Thirty volumes were issued in 59 parts, with 22,426 pages and 565 plates.