LEMURS, lemerz, the curious monkey like animals, or °half-apes') forming the group Lemuroidea within the order Primates, where they stand lowest in rank. They are divisible into three families, Lemuridce, Tarsiidce and The last contains only the aye aye (q.v.) ; and the second only the Malayan tarsiers (q.v.). The lemurs proper (Lemuridce) are confined mainly to Madagascar, hut a few are found upon the African continent, and a few others, of peculiar genera, in the Oriental region. They are chiefly arboreal, and more squirrel-like than monkey-like in their man ners, and quite harmless, gentle and tamable. They are usally mouse-gray or yellowish, not marked in ornamental ways, the hair is long and often woolly, and the tail usually long, bushy and never prehensile. The hind-legs are longer than the fore-legs in the true le mures, which move about on all fours, not using their hands as do monkeys, although the thumbs are opposable; the second toe always has a sharp claw, while the other digits bear nails. In the internal anatomy many features are different from the rule of structure else where in the order. The simplicity of the brain, the fact that certain arteries form retia mirabilia, and especially the non-deciduate con dition of the placenta, are prominent among these lemuroid peculiarities. In general, how ever, the lemurs show much resemblance to the Anthropoidea.
The Lemuridte, or lemurs proper, are divis ible into four groups or sub-families. The first group (Indrisina) is limited to Madagascar, and includes several genera distinguished prom inently by the great size of the hind-legs, as compared with the fore-limbs; and when upon the ground these lemurs walk erect, balancing themselves by holding their short arms above their heads. The largest is the indri (q.v.), which has no visible tail, while the smallest are the avahis (genus Avahis) which are the size of gray squirrels, but have very long tails. A third important genus is Propithecus, con taining several large brightly colored species, called sifakas, which are mainly vetketarian, go about in large bands like the indris and seek food in the daytime, whereas the avahis are nocturnal; and are often tamed and taught to hunt like dogs.
The most typical Lemurs are in the sub family Lemurince, which contains several gen era, some of which inhabit the Comoro Islands as well as Madagascar. Their limbs are of nearly equal length, and they have a fuller dentition (36 teeth). Among the best known are the so-called "gentle" lemurs; the noctur nal grass-eating bokomboulis (Haplemur); and the handsome and highly arboreal species of the type-genus Lemur, which vary greatly in habits, food and appearance. One of these is familiar as the "Madagascar cat" or• ring tailed lemUr (L. catta), since, unlike the rest, it remains upon the ground, especially about rocks, is easily caught and readily tamed. It is remarkable for the fact that the sexes differ in color, the male being black, while the female is reddish brown with white whiskers and ear tufts, and the tail alternately ringed with brown and white. The ruffed lemur (L. var ius) is still more strikingly diversified in black and white, and has a ruff of long hair about the neck. All these lemurs survive captivity well and furnish interesting specimens for all zoological gardens.
The third sub-family is that of the Gala gime, represented in the continent of Africa and in Madagascar. The galagos (q.v.) have long hind-legs, causing them to hop like kan garoos, when on the ground (hut the most of their life is passed in trees), large, semi-nalced ears and long tails. Important genera are Galaqo (q.v.) ; the mouse-lemurs or chirogales (q.v.) ; and the diminutive, squirrel-like dwarf lemurs (Microcebus).
The sub-family Lorisiner contains a group of small lemurs, distributed widely in Africa, India and Malaysia. ((In external appear ance,)) remarks Beddard, "all the three genera of this sub-family agree in their small size, their short or entirely deficient tail, large star ing eyes, and the rudimentary character, or absence, of the index finger, which is never provided with a nail; in all of them the thumb diverges widely from the other fingers, and the great toe is so divergent as to be directed backward? The ears are small and rounded; and the eyes are very large, and situated close together on the front of the head. They feed
on small birds and insects, and are chiefly nocturnal in habits. They inhabit India, Cey lon and the Eastern Archipelago. The genus Nycticebus contains the remarkable ((sloth mon keys or sloth lemur (N. tardigradus), which is nocturnal, howls dismally at times and is the object of many fears and superstitions among the Malays and southern Chinese. The genus Perodictus contains the queer African pottos and angwantibos. The most typical species of the group is the slender loris (Loris gracilis), a pretty little arboreal animal of the Malayan countries. It is described as ((smaller than a squirrel, of exceeding change ness and grace, with beautiful eyes?' The geographical and geological distribution of the lemurs is very interesting. Their re mains are found in the rocks as far back as the transition period (Puerco beds) between the Cretaceous and Tertiary, the oldest occurring in the western United States. These are small lemuroids, and similar forms are found in the early Tertiary rocks of Europe, Asia and Africa. Many genera are known. The most recent, which may have survived in Mad agascar until the discovery of that island by Europeans, was Megaladapis, which must have been three or four times bigger than any mod ern species. The circumstance that existing lemurs and certain other animals occurs only in south-central Africa, Madagascar and the Ori ental region, and nowhere between, was so extraordinary a fact in zoogeography that early attempts to account for it resulted in the hypothesis of an ancient continental land-area, called Lemuria (q.v.) which was supposed to connect Africa and southern Asia. This theory had little other foundation, and the subsequent discovery of remains of extinct lemurs in Europe, western Asia and the two Americas showed that it was needless. It is evident that the existing lemurs are the sur vivors of a once world-wide race which has died out except in certain islands and favor able corners of the world where they are not exposed to cold climates nor to too many enemies. The almost complete absence of pred atory animals in Madagascar doubtless ex plains the comparatively great number of lemurs characteristic of that isolated country.
Consult Beddard, 'Mammalia) (1902) ; For bes, Naturalists' Library) (1894); Lydekker, 'Royal Natural History,) 'Vol. I, (1893); Mivart and Murie, of the Lemuroidea,) (in Trans.-Zool. Soc. of London, Vol. VII 1872) ; Ingersoll, 'Life of Mammals) (New York 1909).
LENA, 1.1.-nr or !Erna, Siberia, one of the largest rivers in the world, draining about 1,000,000 square miles, rising on the north western side of the mountains which skirt the western shore of Lake Baikal, about 180 miles east-northeast of Irkutsk It flows in a wind ing but mainly semi-circular course, north northeast and northwest, receiving the Vitim, the Aldan, the Viliui and other tributaries. Then a mighty stream it flows generally north. About 800 miles from the ocean it is over five miles in width. Near its mouth it separates into branches, forms a great number of del taic islands and discharges itself into the Arc tic Ocean by several mouths in lat. 73° N. and long. about 128° E., having thus passed over 21 degrees of latitude and 22 degrees of longi tude. Its direct course, through a generally barren country interspersed with a few dense forests, but in some parts with valuable min erals, is about 1,4.80 miles; its actual course, windings included, about 2,850 miles. It is navigable through the greater part of its upper course, is rich in fish, is frozen from October to May and disastrous floods are often caused by the melting of ice in its upper parts.