Page:EB1911 - Volume 22.djvu/350

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.
336
PRIMATES


g rem axillary bones projecting but very slightly in front of the maxillae. ody and limbs stout. No tail. Vertebrae: C.7, D.I7, L.6, 5.3, Ca.x2. The single species N. tardigradus, with several races, inhabits eastern Bengal, the Malay countries, Sumatra, Borneo, java, Siam and Cochin China. These lorises lead solitary lives in the recesses of large forests, chiefly in mountainous districts, where they sleep during the day in holes or fissures of large trees, rolled up into a ball, with the head between the hind legs. On the approach of evening they awake, and durin the night ramble among the branchesfof trees slowly, .in search, of food, which consists of leaves and' fruit, small birds, insects and mice. When in quest of living prey they move noiselessly till quite close, and then suddenly seize it with one of their hands. The female produces but one young at a time. In the second genus, represented only by the slender loris (Loris gracilis) of southern India and Ceylon, the upper -incisors are very small and equal. Orbits very large, and only separated in the middle line above by a thin vertical plate of bone. Nasals and premaxillae produced forwards considerably beyond the anterior limits of the maxillae, 'and supporting a pointed nose. Body and limbs slender. No external tail. Vertebrae: C.7, D.I4, L.9, 5.3, Ca.6. The slender loris is about the size of a squirrel, of a yellowish-brown colour, with large, prominent eyes, pointed nose, long thin body, long, angularly bent, slender limbs and no tail. Its habits are like those of the rest of the group. The Indian and Ceylon races are distinct (see LORIS). The African pottos, Perodicticus, differ by the reduction of the index-finger to a mere nailless tubercle, and apparently by the absence of abdominal teats. In the typical section of the genus there is a short tail, about a third of the length of the trunk. Two or three of the anterior dorsal vertebrae have very long slender spinou s processes which in the living animal project beyond the general level of the skin forming distinct conical prominences, covered only by an exceedingly thin and naked integument. P. 'potto, the potto, is one of the oldest known members of the emuroids having been described in 1705 by Bosman, who met with it in his voyage to Guinea. It was, however, lost sight of until 1835, when it was rediscovered in Sierra Leone, It is also found in the Gaboon and the Congo, and is strictly nocturnal and slower in its movements even than Nycticebus tardfigradus, which otherwise it much resembles in its habits. A second species, P. batesi, inhabits the Congo district. A third species, the awantibo (P. calabarensis), rather smaller and more delicately made, with smaller hands and feet and rudimentary tail, constitutes the sub-genus Arctocebus. It is found at Old Calabar, and is very rare. Vertebrae: C.7, D.r5, L.7, 5.3, Ca.9.

Exrmcr PRIMATES

The most interesting of all the extinct representatives of the order is Pithecanthropus erectus' (q;'v.), which is represented by the imperfect roof of a skull, two molars and a femur, discovered in a bed of volcanic ash in ]ava. The forehead is extremely low, with beetling brow-ridges, and the whole calvarium presents a curiously gibbon-like aspect. The capacity of the brain-case is estimated to have equalled two-thirds that of an average modern man. The creature is regarded as transitional between the higher apes, more especially the H ylobatidae and the lowest representatives of the genus Homo, such as the Neanderthal men. From the Lower Pliocene of India has been obtained the palate of a chimpanzee-like ape, which by some is referred to the existing Ahthropapitheczgs, while by others it is considered to represent a, genus by 'itself-Palaeapithecus. The same formation has yielded the canine tooth of a large ape, apparently referable to the existing Asiatic genus Simia. From the Miocene of Europe has been described the genus Dryopithecus, typified by D. fontani, a generalized ape of the size of a chimpanzee, related, perhaps, ~ both to the Simiidae and the Hylobatidae. The Lower Pliocene of Germany has yielded other remains referred °to a distinct genus under the name of Paidopithex rhenanus. From the Miocene of the Vienna basin Dr O. Abel has described certain ape-remains under the name of Griphopilhecus suessi, as well as others regarded as representing a species of Dryopithecus with the name D. darfwini. As regards the first, all that can be said is that it indicates a member of the group to which Dryopithecus belongs. It has been suggested that the latter genus is closely related to man, but this idea is discountenanced by the great relative length of the muzzle and the small space for the tongue. Teeth of another man-like ape from the Tertiary of Swabia, described under the preoccupied name Anthropodus, have been re-named N eopithecus. The genus Anthropodus is represented by remains of an ape of doubtful position from the French Pliocene. Pliopithecus from the French Miocene is certainly' a gibbon, perhaps not distinguishable from H ylobates. I

Oreopithecus, from the Miocene of Tuscany, is perhaps intermediate between gibbons and baboons (Papio), the latter of which, as well as M acacus, are represented in the Indian Pliocene. M esopithecus, of the Grecian Lower Pliocene, presents some characters connecting it with Sewnopithecus and others with Macacus. An allied type from the Lower Pliocene of France is Dolichopithecus, taking its name from the elongated skull; while M acacus occurs in the Upper Pliocene and Pleistocene of several parts of Europe. Cryptopithecus, 'from the Swiss Oligocene, appears to be the oldest known Old World monkey. From the Miocene of Patagonia are known certain monkeys described as Homunculus, Anthropops, &c., apparently more akin to the Cebidae but perhaps representing an extinct family.

Passing on to the lemurs, it may be mentioned in the first place that G. Grandidier has described an extinct lemur from the Tertiary of France, which he believes to be nearly related to the slow lorises, and has accordingly named Pranycticebus gaudryi. If the determination be correct the discovery is of interest as tending to link the modern faunas of "southern India and West Africa (which possess many features in common) with the Tertiary 'fauna of Europe. Certain remarkable extinct lemuroids of large size have been discovered in the superficial deposits of Madagascar, in one of which (M egaladapis) the upper cheek-teeth are of a tritubercular type (fig. 23), while in the second and smaller form (Nesopithecus) the dentition makes a notable approximation to that of the Cercopithecidae. Each

FIG. 23.—Skull and Hinder Right Upper Cheek-teeth of Megaladapis madagascariensis.

of these genera, which probably survived till a very late date, is generally regarded as typifying a family group. In egaladapis the skull is distinguished by its elongation and the small size of the eye-sockets, the tritubercular upper molars presenting considerable resemblance to those of the living Lepidolemur. The brain is of a remarkably low type. In one species the approximate length of the skull is 2 50, and in the second 330 millimetres. Even more interesting are the two large species of N esopithecus, one of which was at first described as Globilemur. They show a very complicated type of brain, and were at first regarded as indicating Malagasy representatives of the Anthropoidea. In regard to the character of the tympanic region of the skull this genus shows several features characteristic of the more typical Malagasy lemuroids; and the eye-sockets are open behind, while the dentition is numerically the same as in some of the latter. On the other hand, in several features Nesopithecus resembles the Anthropoidea; the upper incisors are not separated in the middle line, and the upper molars