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CHIN and See also:SQUIRREL-See also:MONKEY). The second See also:section of the sub-See also:family includes the spider-monkeys (fig. 13), and is characterized by the completely prehensile tail, with the inner See also:surface of the tip naked, the rudimentary See also:condition or See also:absence of the thumb, the laterally compressed and more or less pointed nails, and the absence of an entepicondylar foramen to the humerus. The limbs, too, are very See also:long and slender, with the front pair of greater length than the See also:hind ones. The caecum approximates to that of the Catarrhina, having its terminal extremity pointed. The true spider-monkeys (Aides) lack the thumb, and have the nails but slightly compressed and pointed, the limbs very long, the nasal septum of See also:ordinary width, and the See also:fur not woolly. Nearly all have the See also:hair on the See also:head, except that of the forehead, directed forwards. There are nearly a dozen See also:species. In these monkeys so powerful is the grasp of the tail that the whole See also:body can be sustained by this See also:organ alone. It even serves as a fifth See also:hand, as detached See also:objects, otherwise out of reach, can be grasped by it, and brought towards the hand or mouth. Their prehension is in other respects exceptionally defective, owing to the loss of the thumb. Spider-monkeys are very See also:gentle in disposition; and, by this and their long limbs and fitness for See also:tree-See also:life, seem to represent the See also:gibbons of the Old See also:World. Nevertheless, in spite of their admirable See also:adaptation for arboreal life, their comparatively slow progression offers a marked contrast to the vigorous agility of the gibbons (see SPIDER-MONKEY). The See also: P. satanas of See also:Para and P. chiropotes of See also:Guiana are well-known species. The uakaris (Uacaria or Cothurus) of Amazonia are broadly distinguished from all other Cebidae by their See also:short or rudimentary tails; Ua. calva being remarkable for its brilliant red jaw and See also:pale See also:chestnut hair (see UAEARI). with more forwardly directed eyes, which are not surrounded by a radiating fringe of hair and a wider nasal septum. The titis are-represented by about ten species, of which C. See also:moloch is represented in fig. 16. Most of them are confined to Amazonia, but a few h t t Like t tamong tem . mooc, reace See also:ea coa . e marmoses, The last and lowest representatives of the Cebidae constitute the sub-family Nyctipithecinae, the members of which are See also:cat-like monkeys, with woolly or bushy hair, short, conical muzzles, non-prehensile tails and well-developed thumbs. The brain-case of the See also:skull is not elongated, and the hemispheres of the brain do not cover the cerebellum. The lumbar vertebrae are elongated, with long, See also:sharp, backwardly directed See also:spinal processes; the hinder part of the lower jaw is tall; and there is no laryngeal sac. The long and hooked caecum has its terminal portion constricted. In accordance with their nocturnal habits, the douroucoulis (Nyctipithecus) are easily recognized by their large and closely approximated eyes, which are, however, separated by a See also:complete septum, the comparatively narrow nasal septum, small ears buried in the woolly fur, and long bushy tail. Well-known species are the See also:lemur-like See also:douroucouli (N. felinus, fig. 15) of Amazonia, See also:Peru and See also:Ecuador, and N. vociferans, with a nearly similar See also:distribution. The titis, Callithrix (or Callicebus I), are smaller monkeys (fig. 16), Apparently the name Callithrix was originally given to the marmosets, and if transferred to that group should be replaced by Callicebus.lower canines are not markedly larger than the incisors constituting the typical Hapale, while such as have the lower canines taller than the See also:teeth between them form the genus See also:Midas. These squirrel-like little monkeys, in which the See also:great toe can be opposed to the other toes, range as far See also:north as 15° N., where they are represented by Midas geoffroyi, and as far in the opposite direction as the See also:southern tropic, where M. chrysopygus and M. rosalia occur. The See also:colour and the length of the hair are very variable, some species having long silky pale-chestnut hair (fig. 17) and tufted ears, while in others the hair is comparatively short and See also:black, or black with brown bars, while the ears are not tufted (see See also:MARMOSET). Lemurs, Prosimiae.-Although the likeness generally takes the form of a more or less See also:grotesque See also:caricature, the faces of all monkeys and apes present, in greater or less degree, some resemblance to the human countenance. In the lower group of See also:Primates, commonly known as lemurs, or lemuroids, this resemblance is wholly lost, and the face assumes an elongated and See also:fox-like form, totally devoid of that " expression" which is so characteristic of See also:man and the higher apes and monkeys. uc, Upper canine. pm, Premolars. lc, Lower canine. m, True molars. Lemurs, Prosimiae or Lemuroidea, which form a group See also:con-fined to the tropical regions of the Old World and more numerously represented in See also:Madagascar than elsewhere, are arboreal and for the most part See also:crepuscular or nocturnal Primates, feeding on See also:insects or fruits, or both together and collectively characterized as follows. The tail, which is generally long and thickly haired, is never prehensile. As a See also:rule, there is a single pair of See also:pectoral teats, but an additional abdominal or even inguinal pair may be present. The thumb and great toe are opposable to the other digits, the former being provided with a See also:flat See also:nail, while the second toe is always furnished with a claw; the See also:fourth toe is longer than all the See also:rest, and the second, or See also:index, See also:finger is small or rudimentary. In the skull (fig. 18) the orbital See also:ring is formed by the frontal and jugal bones, and, except in the Tarsiidae, there is a See also:free communication between the See also:orbit and the temporal fossa; the lachrymal foramen is situated outside the orbit (fig. 18); the tympanic either forms a free semicircle in the auditory bulla or enters into the formation of the latter; and the foramen rotundum is generally fused into the sphenoidal fissure. Interparietal bones are frequently developed, and the two halves of the lower jaw are generally welded together in front. Except in the genus Perodicticus, the humerus is furnished with an entepicondylar foramen at the lower end; the centrale of the carpus is generally free; and the femur is usually provided with a third trochanter. The cerebellum is only partially covered by the hemispheres of the brain, which in the See also:medium-sized and larger species conform to the See also:general type of the same parts in monkeys and apes. The normal dental they feed largely upon insects and grubs. Platyrrhina is represented The second and last family of the by the marmosets or oustitis (Hapalidae), all of which are small monkeys, with the ears hairy externally, and nails, except that the of the great toe, claw-like, the thumb non-opposable, the tail long, bushy and non-prehensile, and only two molars in each jaw, the dental See also:formula thus being i. c. 1, p. I, m. . The humerus has no entepicondylar foramen. Three See also:young are produced at a See also:birth. Marmosets are divided into two genera, those in which the formula is i. , c. -, p. 1,m. 1, or the same as in See also:American monkeys; but the upper incisors are small and separated from each other, while the lower ones are large and approximated to the incisor-like canine; the molars have three or four cusps. In all cases the See also:stomach is See also:simple and a caecum present. The testicles are contained in a scrotum, the penis has a See also:bone, the uterus is bicornuate and the urethra perforates the clitoris. The See also:placenta may be either diffuse, with a large allantoic portion, and non-deciduate, or discoidal and deciduate. As a rule, only a single offspring is produced at a birth. Very See also:note-worthy is the occurrence in the See also:females of the See also:Asiatic lorisis of what appears to be the vestige of a marsupial apparatus, attached to the front of the See also:pelvis. Lemur calla also possesses the rudiment of a marsupial See also:fold; while in both sexes of the aye-aye occurs a skin-muscle corresponding to the sphincter marsupii of marsupials. The distribution of existing lemurs is very peculiar, the See also:majority of the species inhabiting Madagascar, where they for the most part dwell in small patches of See also:forest, and form about one-half the entire mammalian See also:fauna of the See also:island. The remaining species inhabit See also:Africa south of the See also:Sahara and the Indo-See also:Malay countries. See also:Tarsier.—The tiny little large-eyed Malay lemuroid known as the tarsier, Tarsius spectrum (or T. tarsius), of the Malay See also:Peninsula and islands, together with its Celebean and Philippine representatives, alone constitutes the section Tarsiina (and the family Tarsiidae), which has the following distinctive characteristics: The lower incisor is See also:vertical and the canine of normal form, while the upper incisors are in contact; the orbit is cut off from the temporal fossa by a bony See also:plate, leaving only a small orbital fissure; the tympanum enters into the formation of the auditory meatus, through which passes the See also:canal for the See also:internal See also:carotid artery; the See also:tibia and fibula in the hind-See also:leg are fused together, and the calcaneum and navicular of the See also:tarsus elongated. The tarsier seems to be a See also:primitive form which makes a certain approximation to the Anthropoidea, and differs from other lemuroids, in the structure of its placenta. The dental formula is i. , c. }, p. 8, m. See also:total 34. Tarsiers have enormous eyes, occupying the whole front of the orbital region, and are purely nocturnal in their habits, living in trees on the branches of which they move by hopping, a See also:power they possess owing to the See also:elongation of the tarsal bones (see TARSIER). Malagasy Lemurs.—All the other Prosimiae may be grouped in a second section, the Lemurina, characterized as follows: The lower incisors and the canine are similar in form and inclined forwards (fig. 18) ; the upper incisors are small and separated by an See also:interval in the See also:middle See also:line; the orbits communicate largely with the temporal fossae; the internal carotid artery enters the skull in advance of the auditory meatus through the foramen lacerum anterius; and the tibia and fibula are See also:separate. The Malagasy lemurs are now all included in the single family Lemuridae, which is confined to Madagascar and the See also:Comoro Islands, and characterized by the tympanic ring lying free in the auditory bulla. The typical sub-family Lemurinae, which includes the majority of the family group, is characterized by all the fingers except the index having flat nails, the elongation of the facial portion of the skull, the large hemispheres of the brain not covering the cerebellum, the occasional presence of two inguinal in addition to the normal pectoral teats, the dental formula i. , c. p. m. °y, with the first upper incisor generally small and sometimes wanting, and the hinder cusps of the upper molars smaller than the front ones. These lemurs are woolly-haired animals, often nearly as large as See also:cats, with the legs longer than the arms, the tail long and bushy, and the spinal processes of the last dorsal and the lumbar vertebrae inclined. In the typical genus Lemur (fig. 19), the tarsus is of normal length, the tail at least half as long as the body, the ears are tufted, there are no inguinal teats, the last premolar is not markedly broader than the others, and the upper molars have a conspicuous cingulum. These lemurs. have long fox-like faces, and habitually walk on the ground or on the branches of trees on all fours, although they can also jump with marvellous agility. They are gregarious, living in small troops, are diurnal in their habits, but most active towards evening, when they make the See also:woods resound with their loud cries, and feed, not only on fruits and buds, but also on eggs, young birds and insects. When at rest or sleeping, they generally coil their long, bushy tails around their bodies, apparently for the See also:sake of the warmth it affords. They have usually a single young one at a birth, which is at first nearly naked, and is carried about, See also:hanging See also:close to and almost concealed by the hair of the See also:mother's belly. After a while the young lemur changes its position and mounts upon the mother's back, where it is carried about until able to climb and leap by itself. One of the most beautiful species is the ring-tailed lemur (L. See also:cotta, fig. 19), of a delicate See also:grey colour, and with a long tail marked with alternating rings of black and See also: Muzzle very short and truncated. Two inguinal teats, in addition to the normal pectoral pair, are present. The last premolar is broader than those in front, and the upper molars lack a distinct cingulum. The typical H. griseus is smaller than any of the true lemurs, of a dark-grey colour, with See also:round face and short ears. It is quite nocturnal, and lives chiefly among bamboos, subsisting on the young shoots. The second species has been named H. simus. In Hapalemur there is no free centrale to the carpus, and the same is the case with the six or seven species of Lepidolemur (Lepilemur), in which the first upper incisor is rddimentary or wanting, while the second may also be wanting in the adult. There are small lemurs, with small pre-maxillae, short snouts, tails shorter than the body, See also:bladder-like mastoid processes, and the upper molars with an inconspicuous cingulum and the hind-cusps of the last two rudimentary; the fourth upper premolar being relatively broad. Mixocebus caniceps is an allied generic type (see LEMUR). The small Malagasy lemurs of the genera Chirogale, Microcebus and Opolemur differ from the preceding in the elongation of the calcaneum and navicular of the tarsus, on which grounds they have been affiliated to the See also:African galagos. The difference in the structure of the tympanum in the two See also:groups indicates, however, that the elongation of the tarsus has been independently developed in each group. These lemurs have short, rounded skulls, large eyes, long hind limbs and tail, large ears, the first upper incisor larger than the second, the last upper premolar much smaller than the first molar and furnished with only one See also:outer See also:cusp, and the mastoid not bladder-like. Some are less than a See also:rat in See also:size, and all are nocturnal. One of the largest, Microcebus furcifer, is reddish-grey, and distinguished by a dark median stripe on its back which divides on the See also:top of the head into two branches, one of which passes forwards above each See also:eye. The most interesting peculiarity of these lemurs is that certain species (Opolemur samati, Chirogale &c.) during the dry See also:season coil themselves up in holes of trees, .and pass into a See also:state of torpidity, like that of the hibernating animals in the See also:winter of See also:northern climates. Before this takes See also:place an immense See also:deposit of See also:fat accumulates upon certain parts of the body, especially the basal portion of the tail. The smallest species, M. pusillus, lives among the slender branches on the tops of the highest trees, feeding on See also:fruit and insects, and making nests like those of birds. In the sub-family Indrisinae the dentition of the adult consists of See also:thirty teeth, usually expressed by the formula i. c. }, p. I, m. ; but possibly i. }, c. i, p. }, in. ¢ In the See also:milk-dentition there are twenty-two teeth, the two additional teeth in the fore part of the lower jaw having no successors in the permanent See also:series. Hind limbs greatly developed, but the tarsus normal, the great toe of large size, and very opposable; the other toes See also:united at their See also:base by a fold of skin, which extends as far as the end of the first phalange. The thumb is but slightly opposable; and all the fingers and toes are hairy. The length of the tail is variable Two pectoral teats. Caecum very large, and See also:colon extremely long and spirally coiled. The brain is large and the See also:thorax wide. The animals of this group are essentially arboreal, and feed exclusively on fruit, leaves, buds and See also:flowers. When they descendteats, inguinal in position, a feature peculiar to this species. All the digits of both feet with pointed, rather compressed claws, except the great toe, which has a flattened nail; middle See also:digit of the hand excessively attenuated. Vertebrae: C.7, D.I2, L.6, S.3, Ca.27 (see AYE-AYE). Galagos and Lorises.—The lemurs of Africa and the Indo-Malay countries—commonly miscalled sloths—differ from the Lemuridae in that the tympanic enters into the formation of the auditory meatus, in consequence of which they are referred to a family by themselves, the Nycticebidae, which is in turn divided into two sub-families, Galaginae and Nycticebinae. The African galagos or Galaginae, which have the same dental formula as the Lemuridae, are distinguished by the elongation of the calcaneum and navicular of the tarsus. In the single genus See also:Galago, with the sub-genera Otolemur and Hemigalago, the last upper premolar, which is nearly as large as the first molar, has two large See also:external cusps. Vertebrae: C.7, D.13, L.6, S.3, Ca.22–26. Tail long, and generally bushy. Ears large, rounded, naked and capable of being folded at the will of the See also:animal. Teats four, two pectoral and two inguinal (see GALAGO). The lorises, Nycticebinae (Lorisinae), are distinguished as follows: Index-finger very short, sometimes rudimentary and nailless. Fore and hind limbs nearly equal in length. Tarsus not specially elongated. Thumb and great toe diverging widely from the other digits, the latter especially being habitually directed backwards. Tail short or rudimentary. Teats two or four. Lorises and pottos (as the African representatives of the group are called) are essentially nocturnal, and remarkable for the slowness of their movements. They are completely arboreal, their limbs being formed only for climbing and clinging to branches, not for See also:jumping or See also:running. They have rounded heads, very large eyes, short ears and thick, short, soft fur. They feed, not only on See also:vegetable substances, but, like many of the Lemuridae, also on insects, eggs and birds, which they steal upon while roosting at See also:night. One of the greatest anatomical peculiarities of these animals is the breaking up of the large arterial trunks of the limbs into numerous small parallel branches, constituting a rete mirabile, which is found also in the sloths, with which the lorises are sometimes confounded on See also:account of the slowness of their movements. The Asiatic lorises, which are divided into two genera, are characterized by the retention of the normal number of phalanges in the small index-finger, and the presence of a pair of See also:minute abdominal teats (From A. Milne-See also:Edwards.) (the existence of which has only recently been discovered by Messrs Annandale and Willey). In the slow lorises, forming the genus Nycticebus (fig. 22), the first upper incisor is larger than the second, which is often See also:early See also:deciduous. Inner margin of the orbits separated from each other by a narrow flat space. Nasal and ('mm Milne-Edwards and Grandidier.) to the ground, which is but seldom, they sit upright on their hind legs, and move from one See also:clump of trees to another by a series of short jumps, holding their arms above them in the See also:air. Among them are the largest members of the See also:order. The genus Indris has the upper incisors sub-equal in size; upper canine larger than the first premolar, muzzle moderately long, ears exserted. Carpus without an os centrale. Tail rudimentary. Vertebrae: C.7, D.12, L.9, S.4, Ca.9. The See also:indri (I. brevicaudatus, fig. 20), discovered by Sonnerat in 178o, is the largest of the group, and has long woolly hair, partly brown and partly white. In the sifakas, Propithecus, of which there appear to be three species, with numerous See also:local races, the second upper incisor is much smaller than the first. Upper canine larger than the first premolar. Muzzle rather short. Ears short, concealed by the fur. An os centrale in the carpus. Tail :orig. vertebrae : C.7, D.12, L.8, S.3, Ca.28. In Avahis, represented only by A. laniger, the second upper incisor is larger than the first. Upper canine scarcely larger than the first premolar. Muzzle very short. Ears very small and hidden in the fur, which is very short and woolly. Carpus without os centrale. Tail long. Vertebrae: C.7, D.II, L.9, S.3, Ca.23 (see INORI and See also:SIFAKA). . The last sub-family, Chiromyinae (formerly regarded as a family), is represented only by the aye-aye, Chiromys (or Daubentonia) madagascariensis, and has the following characteristics: Dentition of adult, i. }, c. p. in. }, total 18. Incisors (fig. 21) very large, compressed, curved, with persistent pulps and See also:enamel only in front, as in rodents. Teeth of cheek-series with flat indistinctly tuberculated crowns. In the young, the first set of teeth more resemble those of normal lemurs, being i. , c. m. , all very small. Four premaxillary bones projecting but very slightly in front of the maxillae. Body and limbs stout. No tail. Vertebrae: C.7, D.r7, L.6, S.3, Cara. The single species N. tardigradus, with several races, in- habits eastern See also:Bengal, the Malay countries, See also:Sumatra, See also:Borneo, See also:Java, See also:Siam and See also:Cochin See also:China. These lorises See also:lead solitary lives in the recesses of large forests, chiefly in mountainous districts, where they See also:sleep during the See also:day in holes or fissures of large trees, rolled up into a See also:ball, with the head between the hind legs. On the approach of evening they awake, and daring the night ramble among the branches of trees slowly, in See also:search of See also:food, which consists of leaves and fruit, small birds, insects and mice. When in quest of living See also: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 See also:time. In the second genus, represented only by the slender See also:loris (Loris gracilis) of southern See also:India and See also: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 See also:nose. Body and limbs slender. No external tail. Vertebrae: C.7, D.14, L.9, S.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 See also:bent, slender limbs and no tail. Its habits are like those of the rest of the group. The See also:Indian and Ceylon races are distinct (see LORIS). The African pottos, Perodicticus, differ by the reduction of the index-finger to a See also: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 See also:trunk. Two or three of the anterior dorsal vertebrae have very long slender spinous 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. See also:potto, the potto, is one of the See also:oldest known members of the lemuroids having been described in 1705 by Bosman, who met with it in his voyage to See also: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 See also:Congo, and is strictly nocturnal and slower in its movements even than Nycticebus tardigradus, which otherwise it much resembles in its habits. A second species, P. batesi, in-habits the Congo See also: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 See also:Calabar, and is very rare. Vertebrae: C.7, D.15, L.7, S.3, Ca.9. Additional information and CommentsThere are no comments yet for this article.
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