1902 Encyclopedia > Lemur

Lemur




LEMUR, a term applied by Linnaeus to a group of mammals, and suggested by the nocturnal habits and strange ghostdike appearance of some of its members. As they had previously no vernacular appellation in English, it has been generally adopted, and is now completely anglicized, making " lemurs " in the plural. The French call them Makis, the Germans Halbaffen, in allusion to their forming, in appearance at least, a transition from monkeys to ordinary quadrupeds. For the same reason they are called Prosimim by some systematic writers. When the name was bestowed by Linnreus, only five species were known, of which one, L. volans, Linn., Gcdeopithecus volans of modern writers, is now removed by common consent from the group. Notwithstanding the discovery of many new and curious forms, the lemurs remain a very natural and circumscribed division of the animal kingdom, though no longer considered a single genus, but divided up into many genera and even families.

The Lemurs, or Lemuroid animals as they ought more properly to be called, were formerly associated with the monkeys in the Linnrean order Primates, and afterwards in the Quadrtimana of Cuvier, forming in that order the third main division, called by Geoffroy St Hilaire Strepsirhina, on account of the twisted form of the external nostrils, a division equivalent in value to the Gatarhina or Old World and the Platyrhina or New World monkeys. As more complete knowledge of their organization has been gradually attained, the interval which separates them structurally from the monkeys has become continually more evident, and they are now considered either as a distinct suborder of the Primates, or even as forming an order apart, without any very near affinities with the animals with which they have hitherto been so closely associated.

The existing species are not numerous, and do not diverge widely in their organization or habits, being all of small or moderate size, all adapted to an arboreal life, climbing with ease, and, as they find their living, which consists of fruits, leaves, birds' eggs, small birds, reptiles, and insects, among the branches of the trees, they rarely have occasion to descend to the ground. None are aquatic, and none burrow in the earth. Many of the species, but by no means all, are nocturnal in their habits, spending the day in sleeping in holes, or rolled up in a ball, perched on a horizontal branch, or in the fork of a tree, and seeking their food by night. Their geographical distribution is very peculiar; by far the larger proportion of species, including all those to which the term " lemur" is now especially restricted, are exclusively inhabitants of Madagascar, where they are so abundant and widely distributed that it is said by M. Grandidier, who has contributed more than any other traveller to enrich our knowledge of the structure and manners of these animals, that there is not a little wood in the whole island in which some of them cannot be found. From Madagascar as a centre a few species less typical in character extend through the African continent westward as far as Senegambia, and others are found in the Oriental region as far east as the Philippine Islands and Celebes.

The following are the essential anatomical characters common to the whole group :—
Teeth heterodont, or divided by their form into incisors, canines, and molars, and diphyodont, or consisting of a first and second set. Molars multicuspidate. Skull with complete bony margin to the orbits, which communicate freely (except in Tarsins) with the temporal fossee. Lacrymal foramen outside the margin of the orbit. Clavicles well developed. Radius and ulna distinct. Scaphoid, lunar, and central bones of the carpus almost always separate. Five digits on the manus and pes, though the index of the manus may be rudimentary. Pollex (or thumb) and hallux (or great toe) always well developed—the latter especially large, opposable to the other digits, and with a flat nail. The index or second digit of the pes always terminating in a long pointed claw. The fingers and toes generally not tapering towards their extremities, but (except in Ghiromys) dilated, flattened,, and rounded at the tips. Cerebral hemispheres not completely overlapping the cerebellum, and but little convoluted. Stomach simple. Caecum always present, generally large. The middle or transverse portion of the colon almost always folded or convoluted on itself. Uterus bicornuate. Placenta non-deciduate, diffused or bell-shaped—the whole of the chorion, except the cephalic pole, being covered with villosities. Allantois of great size.

In subdividing the group for the purpose of a more detailed description of the different animals of which it is composed, it must first be noted that there are two very aberrant forms, each represented by a single species—(1) the little Tarsins of the Indian archipelago, and (2) the singular Ghiromys or aye-aye, which, though an inhabitant of the headquarters of the order, Madagascar, and living in the same forests and under the same external conditions as the most typical lemurs, exhibits a most remarkable specia-lization in the structure of its limbs and teeth, the latter being modified so as to resemble, at least superficially,, those of the rodents, an order in which it was once placed. The differences between these two forms and the remaining lemurs is so great that the whole order naturally divides itself into three families, the. first of which may be again divided into four subfamilies, which with the genera they-contain may be thus arranged :—

== TABLE ==

Upper incisors two on each side, small and separated by an in-terval in the middle line. Upper canines large, conical, compressed, and pointed. Premolars two or three, molars three on each side above and below, with numerous, more or less pointed, cusps. In the front of the lower jaw are on each side two or three closely approximated, long, slender teeth lying almost horizontally and projecting forwards. These are generally considered to represent the incisors and canines, but there is some doubt about their homologies, and they may be all considered as incisors, the canine being absent. The first lower premolar larger than those behind it, and shaped like a canine. The orbit and temporal fossa widely continuous beneath the bar of bone (formed by the frontal and malar) constituting the posterior boundary of the former cavity. The fibula well developed and distinct from the tibia. All the digits of both feet (except the second of the hind foot) with flat nails, and corresponding form of ungual phalanges.

I. Subfamily Indrisinas.—The dentition of the adult consists of thirty teeth, usually expressed by the formula if, c\, pf, m$ ; but, as indicated above, they may be i%, c\, pi, mf. In the milk dentition there are twenty-two teeth, the true molars of course not being represented, but there are two additional teeth in the fore part of the lower jaw which have no successors in the permanent series. Hind limbs greatly developed, but the tarsus normal. Hallux of large size, and very opposable. The other toes united at their base by a fold of skin, which extends as far as the end of the first phalanx. Mamma? two, pectoral. Caecum very large, and colon extremely long and spirally coiled.

The animals of this group are, as their organization indicates, essentially arboreal, and feed exclusively on fruit, leaves, buds, and flowers. When they descend to the ground, which is but seldom, they sit upright on their hind legs, and move from one clump of trees to another by a series of short jumps, holding their arms above them in the air. They are restricted geographically to the island of Madagascar. Among them are the largest members of the order. A very detailed and beautifully illustrated account of their charac-ters, external and internal, and distribution and habits, is given in the Histoire Ncdurclle de Madagascar, by A. Grandidier and Alphonse Milne-Edwards (1875). The species are not numerous and are distributed into three genera.

1. Indris, Geoff.—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. Vertebra?: C7, 1)12, 1.9, S4, C9.
The only well-established species is the indris (I. brecicaudatus, Geoff., fig. 1), discovered by Sonnerat in 1780. It is the largest of the lemurs, the length of the head and body being about 2 feet, and the tail 2 inches. It is very variable in colour, for although usually nearly black, marked with whitish spots principally in the lumbar region and fore arm, individuals have been found quite white. It inhabits exclusively the forests of a part of the east coast of Mada-gascar, living in small troops of four or five in number, and resembling in most of its habits the animals of the next genus.

2. Propithecus, Bennett.—Second upper incisor 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 long. Vertebra :*C7, D12, L8, S3, C28.

The species are all subject to great variations in colour, which has led to much difficulty in discriminating them, and to much con-fusion of synonymy. Grandidier and Milne-Edwards recognize three as certainly distinct:—P. diadema, P. verreauxii, and P. coronatus (fig. 2). Some of these are to be found in almost every part of the island of Madagascar, living in the woods in small bands of six or eight together, and feeding exclusively on buds, flowers, and berries. Their powerful hind limbs enable them to leap from tree to tree, often to a distance of ten yards, without any apparent effort, seem-ing to fly through the air. When obliged to descend to the ground to pass from one clump of trees to another, they do not run on all fours, but stand erect, and throwing their arms above their heads, progress by a series of short jumps, producing an effect which is described by travellers who have seen them thus in their native haunts as exceedingly ludicrous. They are not nocturnal, but most active in the morning and evening, remaining seated or coiled up among the branches during the heat of the day. They are naturally of a quiet and gentle disposition, and do not show much intelli-gence. They are also less vociferous than the true lemurs, only when alarmed or angered making a noise which has been compared to the clucking of a fowl. Like the rest of the subfamily they never have more than one young one at a time.

3. Avahis, Jourdan,—Second upper incisor 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 soft and woolly. Carpus without os centrale. Tail long. Vertebra?: C7, Dll, L9, S3, C23.
One species, A. laniger (Gmelin), the woolly lemur, or avahis, considerably smaller than any of the last group. It differs from them in its habits, being quite nocturnal, and not associating in small troops, but being always met with either alone or in pairs. It is very slow in its movements, and rarely descends to the ground, but when it does it walks upright like the other Indrisinm. It is found throughout the forests which clothe the mountains on the east coast of Madagascar, and also in a limited district on the north-west coast, the specimens from which locality are of smallersize and rather different in colour.
II. Subfamily lemurinee.—The dentition in the adult consists of thirty-six teeth, which as usually enumerated are if, c\, p%, mf. In the forepart of the lower jaw are on each side three elongated, compressed, procumbent teeth, of wdiich the outer, usually consid-ered the homologue of the canine, is larger than the others. All hare long tails. Hind limbs not of the same disproportionate size as in the last group ; and the ca?eum much less developed. Tarsus but slightly elongated, the os calcis being always less than one-fourth the length of the tibia. Toes of the hind feet free to the base. Habitat, Madagascar and some of the adjacent Comoro islands.

This group contains the typical lemurs, or those to which the term is now chiefly restricted. Two rather aberrant members make it necessary to divide it into three genera.

1. Lemur, Linn.—Upper incisors separated by an interval in the middle, but not in contact with each other or the canine, in front of which they are both placed. Muzzle elongated. Ears conspicu-ous and tufted. Mamma; two, pectoral. Vertebra; : C7, D12, L7 (or D13, 1,6), S3, C27.





Animals much about the size of a common cat, with fox-like faces, soft thick fur, and long tails well clothed with hair. Not having the same disproportionate size of the limbs as the last group, they are much more quadrupedal in their actions, walking on the ground or running along the branches of trees on all four feet, but also jump-

lr
Fro. 3.—Skull of Ring-tailed Lemur (Lemur cotta). x f. Mus. Roy. Coll. Surgeons, uc, upper canine ; le, lower canine; pm, premolars ; m, true molars.

ing with marvellous agility. They are gregarious, living in small troops, are diurnal in their habits, but most active towards evening, when they make the 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 sake of the warmth it affords. They have usually either one or two young ones at a birth, which are at first nearly naked, and are carried about, hanging close to and almost concealed by the hair of the mother's

4

FIG. 4.— Ring-tailed Lemur (Lemur cotta). From life.

belly. After a while they change their position and mount upon the mother's back, where they are carried about until they are able to climb and leap by themselves. Though no member of the Indrisinse has as yet lived long enough in captivity to be brought alive to Europe, the lemurs are commonly seen in menageries, and often breed in England. They present a great tendency to variation in their colouring, in consequence of which many nominal species have been made. The most distinct, and at the same time most beautiful, is the ring-tailed lemur (L. catta, Linn., fig. 4), of a delicate grey colour, and with a long tail marked with alternating rings of black and white. This is said by Mr G. A. Shaw (Proc. Zool. Soc, 1879, p. 132) to be an exception to all the other lemurs in not being arboreal, but living chiefly among rocks and bushes. Pollen, however, says that it inhabits the forests of the south-west parts of Madagascar, living, like its congeners, in considerable troups, and not differing from them in its habits. He adds that it is extremely gentle, and active and graceful in its movements, and utters at intervals a little plaintive cry like that of a domestic cat. All the others have the tail of uniform colour. The largest species is L. varius, Geoff., the ruffed lemur, sometimes black and white, and sometimes reddish-brown, the variation apparently not depending on sex or age, but on the individual. In L. macaco the male is black and the female red. L. mongoz, L. collaris, and L. albifrons are other well-known species.

2. Hapalemur, Is. Geoff.—Upper incisors very small, subequal, separated widely in the middle line. Those of each side in contact with each other and with the canine, the posterior one being placed on the inside, and not in front of the latter. Muzzle very short and truncated. Mammse four. There is apparently but one species, H. griseus, smaller than any of the true lemurs, of a dark grey colour, with round face and short ears. It is quite nocturnal, and lives chiefly among bamboos, subsisting on the young shoots. A second species has been named H. simus, but it is doubtful if it is not only a variety.

3. Lepilemur, Is. Geoff.; Lepidolcmur and Myxocebus, Peters. —Upper incisors absent or only two in number and very small. Muzzle more elongated than in the last. No distinct os centrale in the carpus. L. mustelinus is the best known species. It has, at all events when adult, no upper incisors. It is rare, and like Hapalemur nocturnal in its habits. A second closely allied species, but with better developed premaxiHoe, containing a pair of smalt styliform incisors, has been described by Peters under the name of Myxocebus caniceps (Monatsb. Berlin. Akacl., 1874, p. 690).

III. Subfamily Galaginse.—Dentition as in Lemurinm, from which they are distinguished by the elongation of the tarsus, caused by a peculiar modification of the os calcis and the naviculare, the distal portion of the former and the whole of the latter having the form of nearly cylindrical rods placed side by side, while the other bones retain nearly their normal form and proportion.

1. Chirogaleus, Geoff.—Third upper premolar very much smaller than the first molar, and with only one external cusp. The ani-mals included under this name appear to form a transition between the true lemurs and the galagos. The genus was originally estab-lished by Geoffroy St Hilaire in 1812 for the reception of three animals only known at that time by drawings made in Madagascar by the traveller Commerson. Subsequent discoveries have brought to light several species that may be referred to it, including one or two which are sometimes considered as forming a genus apart under the name of Microcebus. They are all small, some being less than a rat in size, long-tailed, and nocturnal in their habits. One of the largest, 67. farcifer, is of a reddish-grey colour, and is distinguished by a dark median stripe on its back which divides on the top of the head into two branches, one of which passes forwards above each eye. The most interesting peculiarity of these animals, a knowledge of which we owe to M. Grandidier, is that certain species (O. samati, 0. gliroides, 0. milii, &c.) during the dry season coil themselves up in holes of trees, and pass into a state of torpidity, like that of the hibernating animals in the winter of northern climates. Before this takes place, an immense deposit of fat accu-mulates upon certain parts of the body, especially upon the basal portion of the tail, which has then dimensions corresponding to that of the well known fat-tailed sheep of the Cape, but which by the time they emerge from their torpor has acquired its normal pro-portions. The smallest species, to wdiich many names have been given (0. pusillus, rufus, smithii, &c.), lives among the small branches on the tops of the highest trees, feeding on fruit and insects, and making nests which resemble those of birds.

2. Galago, Geoff. = Otolicnus, Illiger.—Third upper premolar with two large external cusps, and nearly equalling the first molar in size. Os calcis about one-third the length of the tibia, and the navi-culare much longer than the cuboid. Vertebra;: C7, D13, L6, S3, C22-26. Tail long, and generally bushy. Ears large, rounded, naked, and capable of being folded at the will of the animal. Mamma; four, two pectoral and two inguinal.
The galagos differ from all the lemuroids previously mentioned, inasmuch as they are all inhabitants, not of Madagascar, but of the African continent, being widely distributed in the wooded districts from Senegambia in the west to Abyssinia in the east, and as far south as Natal. They pass the day in sleep, but are very active at night, feeding on fruit, insects, and small birds. "When they descend to the ground they sit upright, and move about by jump-ing with their hind legs, like jerboas and kangaroos. They are pretty little animals, varying in size from that of a small cat to less than a rat, with large eyes and ears, soft woolly fur, and long tails. There are several species, of which 67. crassicaudatus, from Mozambique, is the largest. A similar species, or perhaps variety, from Angola is 67. moiitieri. 67. garnetti, alleni, maholi, demidoffi, and senegalensis are other recognized species. The last-mentioned was the first known to science, having been brought from Senegal by Adanson, and described in 1796 by Geoffroy, who adopted the name Galago, by which it was said to be called by the natives.

IV. Subfamily Lorisinae.—Dental formula as in Lemurinse. In-dex finger very short, sometimes rudimentary and nailless. Fore and hind limbs nearly equal in length. Tarsus not specially elon-gated. Pollex and hallux diverging widely from the other digits, the hallux especially being habitually directed backwards. Tail short or quite rudimentary. Mammas two, pectoral.

A small group of very peculiar animals, of essentially nocturnal habits, 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 jumping or running. They have rounded heads, very large eyes, short ears, and thick, short, soft fur. They feed, not only on vegetable substances, but, like many of the Lemnridai, also on insects, eggs, and birds, which they steal upon while roosting at night. None of the species are found in Madagascar. 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 true sloths, with which the loris are sometimes confounded on account of the slowness of their move-ments. The animals of this group are usually divided into four genera, though the characters by which they are separated are very trivial. There are more properly two natural divisions.

A. Characterized by the index finger being small, but having the complete number of phalanges, and by their Asiatic habitat.

These form the genus Loris of Geoffroy St Hilaire (1796), Stenops of Illiger (1811), but they were in 1812 divided by Geoffroy into two genera, Nycticebus and Loris, a division which has been accepted by most modern zoologists.
Genus Nycticebus, Geoff.—First upper incisor larger than the second, which is often early deciduous. Inner margin of the orbits separated from each other by a narrow flat space. Nasal and pre-maxillary bones projecting but very slightly in front of the maxilla?. Body and limbs stout. No tail. Vertebra?: C7, D17, L6, S3, C12. The species are N. tardigradus, the common slow lemur or loris, of the Malay countries, Sumatra, and Borneo; N. javanicus, »f Java; andiV. cinereus (fig. 5), of Siam and Cochin China. The

FIG. 5.—Grey Loris (Nycticebus cinereus). From A. Milne-Edwards, N. Archives du Museum, tome iii. pi. 3.

habits of all are much alike. They lead a solitary life 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 during the night they ramble among the branches of trees, slowly and quietly, in search of their food, which consists of tender 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 one at a time. L. tardigradus was placed by Linna?us at the head of the list of species of his genus Lemur, and its habits doubtless suggested the generic name which was trans-ferred by Geoffroy to the less nocturnal and spectre-like Madagascar members of the group.

Bijdragen tot de Bierkunde, part i., Amsterdam, 184S-54.

Genus Loris, Geoff.—Upper incisors very small and equal. Orbits very large, and only separated in the middle line above by a thin vertical plate of bone. Nasals and premaxilla? produced for-wards considerably beyond the anterior limits of the maxilla?, and supporting a pointed nose. Body and limbs slender. No external tail. Vertebra?: C7, D14, L9, S3, C6.
One species, L. gracilis, the slender loris of Ceylon, a very strange-looking creature, 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.

B. Index finger reduced to a mere tubercle without nail. Both the known species are from West Africa.

Genus Perodicticus, Bennett. —A short tail, about a third of the length of the trunk. Two or three of the anterior dorsal vertebra? have very long slender spinous processes which in the living animal project beyond the general level of the skin, forming distinct coni-cal prominences, covered only by an exceedingly thin and naked integument. P. potto (Lemurpotto, Gmelin), the potto, is one of the oldest known members of the lemuroid group, having been de-scribed in 1705 by Bosman, who met with it in his voyage to Guinea. It was, however, lost sight of until 1825, when it was re-discovered in Sierra Leone and fully described by Bennett in the Proceedings of (lie Zoological Society, part i., 1830-31, under the name of Perodicticus Geoffroyi. Bennett's generic name has been retained, but the specific name bestowed by Gmelin, adopted from Bosman, has been restored. It is also found in the Gaboon. It is strictly nocturnal, and slower in its movements even than Nycticebus tardi-gradus, which otherwise it much resembles in its habits.





A second species, the awantibo (P. ealabarensis, Smith), rather smaller and more delicately made, with smaller hands and feet, and rudimentary tail, constitutes the genus Arctocebus, Gray. It is found at Old Calabar, and is very rare, only a few individuals having as yet been met with. Its anatomy has been described by Professor Huxley in theProc. Zool. Soc, 1864, p. 314. Vertebra?: C7, D15, L7, S3, C9.

Family TARSIIM.

Dentition, if, Cf, p%, mf=f, total 34. The first upper incisor large, and in contact with its fellow of the opposite side. Canine of moderate size. Molars, with numerous pointed cusps. Lower canine semi-erect, its apex diverging from that of the single incisor. First lower premolar smaller than those behind it. Orbit to a large extent separated from the temporal fossa by a bony partition. Fibula slender, with its lower half confluent with the tibia. Second and third digits of the hind foot with compressed claws ; all the other digits of both feet with flat nails. Calcaneum and navicular bone of the foot elongated as in the chirogales and galagos, but to a still greater extent. Colon short and not folded. Vertebra?: C7, D13, L6, S3, C27.

This family contains the single genus Tarsius, Storr, of which but one species is known, T. spectrum, the tarsier, a very singular little animal, rather smaller than an English squirrel, with very large eyes and ears, a long thin tail, tufted at the end, and immensely elon-gated tarsal portion of the foot, in allusion to which its generic name was given to it. It inhabits the forests of many of the islands of the Indo-Malayan archipelago, Sumatra, Borneo, Celebes, and some of the Philippines, feeds chiefly on insects and lizards, sleeps during the day, but is tolerably active at night, moving chiefly by jumping from place to place, an action for which the structure of its hind legs, which present a curious resemblance to those of a frog, seems particularly well adapted. It is rare, not more than two being generally found together, and only brings forth one young at a time.

Family CHIROMYID.E. Dentition of adult, if, c%, pi, »!$_=$, total 18. Incisors very large, compressed, curved, with persistent pulps and enamel only in front as in rodents. Teeth of molar series with flat, very indistinctly tuberculated crowns. In the young, the first set of teeth more resemble those of the normal lemurs, being H, el, mf, all very small. Orbit surrounded by a ring of bone posteriorly, beneath which it communicates freely with the temporal fossa. Fibula well-developed and distinct from the tibia. All the digits of both feet with pointed rather compressed claws, except the hallux, which has a flattened nail. Middle digit of the hand excessively attenuated. Vertebra?: C7, D12, L6, S3, C27.

This family, like the last, is formed for the reception of a single genus, Chiromys, Cuvier, eontainingone species, C. madagascariensis (Gmelin), the aye-aye, an animal about the size of a cat, with a broad rounded head, short face, and large and naked ears. It has very large hands and long thin fingers with pointed claws, one of which (the middle or third) is remarkable for its extreme slenderness. The foot resembles that of the other lemurs in its large opposable hallux, with a flat nail, but all the other toes have pointed compressed claws, like that of the second toe in the Lemurinee and the second and third in the Tarsiidas. Tail long and bushy. General colour dark brown, the outer fur being long and rather loose, with a woolly undercoat. Mamma; two, inguinal in position. It is a native of Madagascar, where it was discovered by Sonnerat in 1780. The specimen brought to Paris by that traveller was the only one known until 1860. Since then many others have been obtained, and one has lived for several years in the gardens of the Zoological Society of London. Like so many of the lemurs, it is completely nocturnal in its habits, living either alone or in pairs, chiefly in the bamboo forests. Observations upon captive specimens have led to the conclusion that it feeds principally on succulent juices,

Fro. 6.—Skuil of Aye-aye (Ghiromys madagascariensis). x f. Mus. Roy. Coll. Surgeons.

especially of the sugar cane, which it obtains by tearing open the hard woody circumference of the stalk with its strong incisor teeth. It is said also to devour certain species of wood-boring cater-pillars, which it obtains by first cutting down with its teeth upon their burrows, and then picking them out of their retreat with the claw of its attenuated middle finger. It constructs large ball-like nests of dried leaves, lodged in a fork of the branches of a large tree, and with the opening on one side. The resemblance of its teeth to those so characteristic of the Itodentia caused it to be placed for-merly in that order, and it was only when its anatomical characters were fully known that its true affinities with the lemurs became apparent.

Extinct Lemnroidea.—The disputed zoological position of the lemurs, and the great importance which has been attached to them by those naturalists who regard them as the direct transition between the lower and higher mammals, and survivors of a large group, now almost extinct, through which the higher Primates, including man, must have passed in the progress of their development, make the consideration of their ancient history one of great interest. Until very recently fossil lemurs were quite unknown ; at all events the affinities of certain remains provisionally assigned to the group were much questioned ; but within the last few years the existence of lemuroid animals in Europe during the later Eocene and early Miocene periods has been perfectly established, and remains of a large number of animals attributed, though with less certainty, to the group have been found in beds of corresponding age in North America. In 1862 Rûtimeyer described the fragment of a right maxilla and three molars from a sidero-litic deposit (Bohnerz) at Egerkingen, near Soleure, under the name of Cmnopithecus lemuroides, supposing them to belong to an animal partaking of the characters of the American monkeys and the lemurs. The remains were, however, by most other palaeontologists referred to the Ungulata. More recently M. Bétille discovered in deposits which were being worked for phosphate of lime at Sainte Néboule de Béduer, department of Lot, France, regarded as of early Miocene age, a nearly complete cranium, and subsequently, at the same place, a portion of a ramus of a mandible of apparently the same species of animal. These were described by M. Delfortrie in the Actes de la Société Linnêenne de Bordeaux for 1872 under the name of _Palxolemur betillei. The cranium is generally well preserved, but unfortunately the anterior part, containing the incisor and canine teeth, has been broken off. Its affinity to the lemurine animals, especially to the African forms, the Lorisinx and Galaginx, is chiefly shown by the general form of the cranium, the large size and anterior direction of the orbits, the small and narrow muzzle, and the position of the lacrymal foramen outside the anterior edge of the orbit. In size the fossil is intermediate between the potto (Perodicticus potto) and Galago crassicaudatus. When the specimen came into the hands of M. Gaudry, that experienced and accurate palaeontologist, with the rich treasures of the Paris Museum at hand for comparison, recognized that certain more or less fragmentary remains which had long been in the collection, and had been described from the teeth alone, and generally, though doubtfully referred to the Ungulata, were really nothing more than animals of the same group, and probably even the same species as Palxolemur betillei. These were Adapis parisiensis, Cuvier, from the Paris gypsum, described and figured in the Ossemens fossiles, Aphelo-therium duvernoyi, Gervais, from the same beds, and other specimens from Barthélémy, near Apt. This result was fully acquiesced in by Gervais, who also added Cxnopithecus lemuroides, Rutimeyer, to the synonyms of the animal, which henceforth must be called Adapis parisiensis, as that was the name first assigned to it.

M. Delfortrie's announcement of a fossil lemur from the south of France was soon followed by that of another species by M. PL Filhol, named Necrolemur antiquus (Comptes Pendus, 1873, torn, lxxvii. p. 1111), which was afterwards more fully described and figured (Annales des Sciences Géologiques, torn. v. No. 4, 1874, and Recherches sur les Phosphorites du Quercy, 1876), and a second species of Adapis, of considerably larger size, A. magnus, Filhol, was added to the group ; the latter, of which the skull is upwards of 4 inches in length, resembles M. Delfortrie's in its general characters, but modified much in the way that the skulls of larger animals differ from the smaller ones of the same natural group. The brain-chamber and orbits are relatively smaller, the face larger, the muscular crests more developed, and the constriction between the cerebral and facial portion of the skull more marked. These modifica-tions remove the skull in its general characters still further from the existing lemurs—so much so that M. Filhol refers it and the other species of Adapis to a distinct and hitherto unknown zoological type, intermediate between the lemurs and the pachyderms, to which he gives the name of Pachylemur. On the other hand he considers the Necro-lemur antiquus found at St Antonin, which is a very small species, to be a true lemuroid, more nearly resembling Galago senegcdeusis than any existing species. Unfortu-nately in all these specimens the anterior part of the skull is so much injured that the character and numbers of the incisor teeth cannot be ascertained, a great want in determining the affinities of these animals. And even if the whole of the skulls were found, as long as nothing is known of the limbs, or of any other bones of the skeleton, the determination of their actual zoological position can only be considered as provisional. All the existing lemurs and pachyderms, or ungulates as they are now generally termed, are so essentially different in structure and mode of life that it is difficult to conceive of a transition from one to the other, and therefore any such forms when found will be full of interest. In skull and teeth characters, as far as they are yet known, these ancient lemur-like animals from France do not deviate sufficiently from the existing lemuroids to justify their separation, but it remains to be proved whether they had the opposable hallux and ungui-culate toes of the forms which now inhabit the world, or whether their limbs were of a more generalized type. The discassions which have taken place on their nature at all events show how little reliance can be placed upon the characters of the molar teeth alone in judging of the affinities of an extinct animal.

Perhaps the most important of all the numerous recent palaeontological discoveries in the Tertiary beds of the rocky mountain district of North America has been that of animals wdiich their describers believe to be low and generalized forms of the order Primates. Their existence was not suspected till 1872, in which year Professor Marsh and Professor Cope almost simultaneously announced the fact. Since that time numerous genera have been assigned to the group, including five which were previously described by Leidy from teeth alone, the nature of which he did not venture to determine. These are nearly all from the Eocene or lowest Miocene formations. Until we receive fuller information regarding the remains of these animals, it is premature to speculate upon their real character or affinities. The difficulty of doing so is at present enhanced by their describers in the provisional accounts already given adopt-ing the old assumption that lemurs and monkeys are animals of the same general type, and speaking of them sometimes as one and sometimes as the other. It is possible that these animals, or some of them, may have been monkeys, in which case they were not lemurs ; or they may have been lemurs, in which case they were not monkeys. It is possible also that they may form a connect-ing link between the two, and so justify their old associa-tion in one group. The recently described Anaptomorphus homunculus from the Lower Eocene of Wyoming, an ani-mal smaller than Tardus spectrum, is considered by Cope to be " the most simian lemur yet discovered, and prob-ably representing the family from which the true monkeys and men were derived " (Palxontological Bulletin, No. 34, February 20, 1882). In this case the lemurs, which, judging by their present distribution, appear to have spread east and west from Madagascar, may have had quite a different origin.

Literature.—Besides the works and memoirs on particular families and genera referred to above, see St G. Mivart, "Notes on the Crania and Dentition of the Lemuridae," in Proc. Zool. Sue, 1864 (p. 611-648) and 1S67 (p. 960-975) ; Mivart and Murie, " On the Anatomy of the Lemuroidea," in Trans. Zool. Soc., vol. vii., 1872, pp. 1-113 ; W. Turner, "On the Placentation of the Lemurs," in Phil. Trans., clxvi., pp. 569-587 ; F. Pollen and D. C. Van Dam, Recherches sur la Faune de Madagascar, 2me parte, "Mammifères," 1868. (W. H. F.)




Footnotes

For the arguments in favour of the latter view see Alphonse Milne-Edwards, "Observations sur quelques points de l'embryologie îles Lémuriens et sur les affinités zoologiques de ces animaux," in the Ann. des Sciences Nat., October 1871 ; and P. Gervais, "Encéphale des Lémures," in Journ. de Zoologie, torn. i. p. 7. For those for retaining them among the Primates, see Mivart, " On Lepilemur and Chirogaleus, and on the Zoological Rank of the Lemuroidea," in Proc. Zool. Soc, 1873, p. 484.
For the arguments in favour of the latter view see Alphonse Milne-Edwards, "Observations sur quelques points de l'embryologie îles Lémuriens et sur les affinités zoologiques de ces animaux," in the Ann. des Sciences Nat., October 1871 ; and P. Gervais, "Encéphale des Lémures," in Journ. de Zoologie, torn. i. p. 7. For those for retaining them among the Primates, see Mivart, " On Lepilemur and Chirogaleus, and on the Zoological Rank of the Lemuroidea," in Proc. Zool. Soc, 1873, p. 484.

For the anatomy of this genus, see J. L. C. Shroeder van der Kolk and W. Vrolik, 11 Recherches d'Anatomie comparee sur ]e genre Stenops d'llliger," in
Van der Hoeven and Van Campen, " Ontleedkundig onderzoek van der Potts van Bosman," in Verh. Kong. Akad. van Wetenschappm, Amsterdam, 1859.
H. Burmeister, Beitrage zur ndhreren Kenntniss der Gattung Tarsius, Berlin, 1846.
It was first named Daubentonia by Geoffroy; but this name was withdrawn by its author in favour of Chiromys, as it had been previously given to a genus in the vegetable kingdom. It ought not, therefore, to be revived, as has been done by some modern authors.

R. Owen, " On the Aye-aye," in Trans. Zool. Soc, vol. v. p. 33, 1862; W. Peters, " Ueber die Saugethier-Gattung Ghiromys," in Abhand. Konigl. Akad. der Wissenschaften, Berlin, 1865, p. 79.




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