Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/723

Rh CLIMATE.] AMERICA 081 coast of America, in the middle latitudes, lias nearly as mild and equable a climate as the west coast of Europe. The climate of the great central valley, or basin of the Mississippi, has a considerable affinity to that of the east coast. It was long a matter of dispute in what the difference between the two consists, but this seems at last to have been clearly settled by the meteorological registers kept at the military posts of the United States. From a comparison of four of these registers, from posts near the centre of this great val ley, with others kept on the Atlantic coast in the same latitudes, it appears that the extremes of heat and cold in the basin of the Mississippi are from 5 to 6 higher and lower than on the coasts of New England. The pro portion of fair weather to cloudy is as 5 to 1 in favour of the east coast. The climate of the interior, therefore, exhibits in still greater excess those extremes of tem perature which distinguish the eastern coast of this con tinent from the western, and from the shores of Europe. The fourth region of extra-tropical America includes the parts beyond Mount St Elias on the west coast, and, in the interior, the plains extending from the 50th parallel to the Polar Seas. The intensity of the cold in this tract of country is scarcely equalled by anything that is known under the same parallels in Northern Asia. The northernmost spot in America where grain is raised is at Lord Selkirk s colony, on Red River, in latitude 50. Wheat, and also maize, which requires a high summer heat, are cultivated here. Barley would certainly grow as far north as Fort Chippewyan, in latitude 58f, where the heat of the four summer months was found by Captain Franklin to be 4 higher than at Edinburgh. There is even reason to believe, that both this species of grain and potatoes might thrive as far north as Slave Lake, since the spruce fir attains the height of 50 feet three degrees farther north, at Fort Franklin, in latitude 65. These, however, are low and sheltered spots; but in this dreary waste generally, it will not be found practicable, we suspect, to carry the arts of civilised life beyond the 60th parallel; and the desirable country, capable of supporting a large population, and meriting the name of temperate, can scarcely be said to extend beyond the 52d parallel. At 65 the snow covers the ground in winter to the depth of only two feet, but small lakes continue frozen for eight months. The sea is open only for a few weeks, fogs darken the surface, and the thermometer in February descended in one instance to minus 58, or 90 below the freezing point. At Melville Island, under the 75th parallel, such is the frightful rigour of the climate, that the temperature of the year falls 1 or 2 below the zero of Fahrenheit s scale. It is a peculiarity in the climate of America, that beyond the parallel of 50 or 52, it seems to become suddenly severe at both extremities. At the one, summer disappears from the circle of the seasons; at the other, winter is armed with double terrors. ology : The zoology of America is especially interesting, on iminalia. accoun t O f t ue contrast which exists between the faunas of the north and south portions of the continent a contrast which is especially exhibited in the case of the Mammalia. The zoological province which naturalists mark off as con stituted by South America and part of Central America has been termed the neotropical region, and the area whica has the nearest relationship to this is the Indian region. As regards South America, the Andes have the highest value as zoological boundaries; next to them in importance are the rivers, and then the confines of iiulru- the forest region. The Quadrumana are well represented, ana. and are especially characteristic of the forest region which principally prevails in the western half of the con tinent. None are known to occur on the west side of the Andes south of Guayaquil. The sub-order Platyrhina is peculiar to South America, and so far as research has yet extended, it is not known even to have existed on any other area. On the other hand, no catarhine or lemurine Quadrumana have yet been found in South America. Some of the lower forms of monkey appear to have some affinity with the Lemuridae, which occur in India, Africa, and Madagascar. There are two families, viz., the Cebidse and Hapalida?, all the members of which are strictly arboreal in habits. Some of these monkeys are the most highly developed tree-climbers known, and in many cases they rarely if ever descend to the ground ; and since the monkeys of South America have never been seen to swim, it might be expected that the broad streams of the continent effectually limit the distribution of certain monkeys. The largest species is Lagothrix Humboldtii, so that as a whole the American monkeys are smaller than those of Asia and Africa. As they are the most powerful of arboreal Mammalia, they rule the forests, and this may in part account for the scarcity of squirrels in this region. The Cebidre have a wide range, extending from the south of Mexico to the Uruguay. They include the highest forms of American monkey, and its most specialised representatives are those which have the best adaptation for Life in trees, as may be exemplified by Ateles, with its long limbs and prehensile tail. This latter organ serves all the purposes of a fifth hand; the under surface is bare and provided with tactile papilla;, so that a monkey not only holds by, but also feels with it. It is as mobile and flexible, and in its way as useful to this genus of monkey as is the trunk to the elephant. The genus includes numerous species, the estimate of different natural ists varying from 8 to 40, but about 10 species have been well established. Most of them occur in Brazil and the Guianas ; but each species generally has circumscribed limits. Thus A. jmniscus occurs in the north-east corner of the continent, between the Rio Negro and the Amazon. On the south side of the Amazon its place is taken by another species, A. marginatus. A. Bartlettii occurs on the Upper Amazon. Brachyteles is represented by a single species in South-East Brazil. Several species of Lagothrix have been described, although perhaps all are but varie ties of but one species. L. Humboldtii is confined to the Upper Amazon, west of the Rio Negro, and in some of the contiguous valleys of the Orinoco basin. Mycetes haa six species, ranging from Guatemala to South Brazil. M. seniculus occurs on the north side of the Lower Amazon : M. caraya on the Upper Amazon ; and M. behebutJi is the species which occurs near Para, and south cf the Lowei Amazon. All the above genera have prehensile tails, with bare under surfaces. Nyctipithecus, with three or four species, occurs in the upper portions of the Rio Negro, Amazon, and Orinoco basins. Callithrix ranges over the same ground, but also extends into South-East Brazil. Cnrysothrix occurs throughout the northern part of the region. The genus Pithecia (including Brachyurus) is represented by about 12 species in the Amazon basin. P. irrorata is confined to the south bank of the Upper Amazon ; another species only occurs on the north side to the west of the Rio Negro. P. satanas is the species east of the Rio Negro, and there is a species limited to the south side of the Upper Amazon. The family Hapalidse, or marmosets, has about 30 species, belonging to the genera Hapale and Midas, which range throughout the forests of South America. One species, 11. cedipus, occurs in Costa Rica, but this is the northernmost limit of the family. It seems that the distribution of the monkeys is restricted to the areas clad with continuous forests, so that the absence of monkeys in the Pampean, Andisian, and Peruvian sub-regions is mainly due to the absence of continuous forests. It is also notice able that the sub-orders, families, and genera extend over thr greater portion of the Brazilian sub-region ; whereas in I. 86