The Group of Old World Monkeys, in addition to the baboons, contains several species worthy of special remark. There are some which have tails so very short and insignificant that they seem to be tailless, and several of them are called “apes.” _They are not true anthropoids_ (manlike apes), however, and it is a confusing error to designate any of them as “apes.” The species referred to are the following: The Black “Ape,” of Celebes, exceedingly like a true baboon. The Magot, or Barbary “Ape,” of North Africa and Gibraltar, which is a true macaque. The Japanese Red-Faced Monkey, another macaque, with a brilliant red face, and long, thick coat of hair, which enables it to live out of doors all winter, even in this Zoological Park. The Pig-Tailed Monkey, several species of which are found in Burma and other portions of southeastern Asia. All the above are on exhibition in the Primate House, and the outdoor cages. The Rhesus Monkey, of India, is one of the sacred species, and ages of immunity from molestation, or even wholesome discipline, have made this animal aggressive and domineering in temper. The Bonneted Macaque is the best-tempered monkey of all the monkey species found in the East Indies, and it is by far the best to keep as a pet. The Entellus Monkey, of India, is also a sacred species, and its natural seriousness of manner, and dignified bearing, quite befit the direct descendants of the original Hunuman, or monkey deity of the Hindoos, who helped to build Adam’s Bridge. Of the many African monkeys, some of the most showy (such as the Guerzas and Colobos) are so difficult to procure they can not be set forth as permanent residents in the Primate House. The following species, however, may be classed with the reliables: The White-Collared Mangabey and Sooty Mangabey are both so lively, so good-natured, and so free from the fighting habit, they are prime favorites with everybody. The Mona Monkey is handsome and easily kept, and an excellent representative of the great African genus _Cercopithecus_. The Green Monkey and the Vervet are lively but quarrelsome, and at times become dangerous. The Patas, or Red Monkey, is very sedate, and makes a good cage-mate for the mona. The New World Monkeys, even at their best, never make a strong showing in a vivarium. The trouble is that many of the most interesting species are so delicate it is impossible to keep them alive in captivity. Fame awaits the man who can discover a bill of fare on which Howling Monkeys, Sakis and Yarkees can live in captivity to old age, and repay their cost and care. Their digestive organs are delicate, and are subject to derangement from causes so slight they can not be reckoned with.