152 APE in some of the Cercopitheci, notably in the mangabeys, the muzzle has acquired a greater prolongation. This becomes still more marked in the Macaci. It is this greater pro duction of muzzle, the greater size in the ischiatic callosi ties, the frequent shortness of the tail, and the different geographical distribution, which can alone be given as differentiating these animals from the Cercopitheci. In some kinds the tail is long. Occasionally (as in the wanderoo, M. silenus) it is tufted at the end and short. Sometimes, as in M. nemestrinus, it is very short, and occasionally, as in M. inuus, it is absent. On account of this absence of tail, this species has sometimes been made the type of a distinct genus, Inuus. Another species, M. niger (from Celebes and Batchian), has, on account of the much greater production of its muzzle, been made the type of another genus, termed Cynopiihecus. The Macaci present us with the most northern forms of apes, namely, that of Gibraltar, and M. speciosus of Japan. Father David has lately brought from Moupin, in Thibet, a new species (M. thibetanus) which inhabits snowy moun tains, and is clothed suitably for such a habitat, in thick and dense fur. In addition to the Macaci already men tioned, we may name the species Sinicus, Pileatus, Aureus, Gynomolgus, Silenus, RJiesus, Nemestrinus, Thibetanus, Ochreatus t Palpebrosus, Brunneus, Rufescens, Rheso-similis, Erythrceus, Cristatus, Tcheliensis, Cyclopis, Inornatus, Sancti-joliannis, Lasiotus, Assamensis, Maurus, Philippin- ensis, and Nigrescens. FIG. 6. The Thibet Macaque (Macacus thibetanus). From Milne-Edwards s Recherches des Alammi/eres, pi. 34. The remaining apes of the Old World are the baboons, which are entirely confined to Africa, and to that part of Asia which is zoologically African, namely, Arabia. These animals, which constitute the genus Cynocephalus, have the characters of the Macaci still further developed in having still larger callosities, and a muzzle so extremely produced as to give the head the appearance of that of a dog, whence their generic name. The general form has also here be come very massive, and the limbs being sub-equal in length, the appearance, like the locomotion, is quadrupedal. But the baboons have not only the muzzle so greatly pro duced, they have also the nostrils terminal in position like those of a hound and unlike what we have yet met with. The species C. gelada of Abyssinia and C. obscurus form exceptions to this condition, as they have the nostrils placed as in the Macaci, on which account they have been made the type of a distinct genus, Theropithecus. In the other Cynocephali, the tail may be moderately long, as in C. hamadryas, or very short, as in the man drill, C. mormon. In the last-named species we again meet with much bulk of body, as it exceeds the chim panzee in this respect. It is also remarkable for its bright coloration, the cheeks being brilliant blue, the FIG. 7. The Babuin Batoon (Cynocephalus babuin). From Archives du Museum, vol. ii. pi. 34. nose vermilion, and the beard golden-yellow. Other species described are Sphinx, Olivaceus, Babuin, Anubis, Obscurus, Doguera, Forearms, and Leucophceus. The baboons are the least arboreal and the least frugi- vorous of the Old World apes, some species, e.g., the chacma of Southern Africa (G. porcarius), living habitually amidst rocks, and feeding on eggs, large insects, and scorpions, as well as on vegetable food. In the whole series of Old World apes we find the same number of different kinds of teeth as in man, the dental formula bein 2-2 1-1 2-2 3-3 16 16 or thirty-two teeth in all. Again, in the whole series the two nostrils are divided the one from the other by a narrow septum ; and if the skull be examined, a long bony tube (the meatus auditorius extemus) is seen to lead in wards on each side to the internal ear. Moreover, the thumbs, when present, are always more or less opposable to the other fingers. In passing to the second family of apes the Cebidce, or apes of the New World we find them to form a very dis tinct and easily-defined group, and a little experience readily enables an observer to pronounce at a glance that a given ape belongs either to the Old or the New World, as the case may be. The Cebidce are more thoroughly arboreal in their habits than are the Simiada?. Ranging over tropical America, they have their headquarters in the forests of Brazil, a region where most animal forms put on a more decidedly arboreal character. Accordingly, it is amongst the Cebidce that we meet with, for the first time, a special arboreal organ namely, a prehensile tail. Such a tail has its free end curled, and capable of grasping with greater or less tenacity the objects about which it coils. Again, in the Cebidae, the septum between the nostrils is broad, instead of narrow, imparting to the physiognomy a markedly different character. In passing to these American apes we entirely lose cheek pouches and ischial callosities ; while the thumb, even where best developed, is capable of but a very partial opposition to the other fingers, bending almost in the same plane with the latter, so as to be more like a fifth finger than a thumb. We also constantly find an additional premolar tooth on each side of each jaw, and
that bony tube, the meatus auditorius externus, is wanting,