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Show 130 :MACLEAY SYSTEM OF ous isolated regtons which enjoy a parity of climate atld other conditions identical or the reverse ? The answet is-that in such' regions the vegetation bea~·s. a genera) resemblance, but the species are nearly all ~Ifier~nt, and there is even, in a considerable measure, a d1vers1ty of fa-milies. . The general facts have been thus stated; in the. arctic and antarctic reo-ions and in those parts of lower lahtudest which from the~ir ele'v ation, possess the same ~old c l"1 ma t e, there is always a similar or anal~gous ~egct?-hon, but f~w species are common ~o the van?us s1tuat.wns. _In hke rnanne.r, the intertropical vegetation of Asm, Afnca, _an~ .. America, are specifically different, t~wu~h generally_ s1mt· lar. The southern region of A_n1~nc~ IS ~qually diverse from that of Africa, a country simtlar In chme, but sepa .. rated by a vast extent of ocean. The vegetation of ~us· tralia, another region similarly placed in respect of ehme, ic:; even more peculiar. These facts are the more remarkable when V\-·e discover that, in most instances, the plants of one reo·ion have thriven when transplanted to another of parallel clime. This V\-·ould show that parity of condi· tion does not lead to a parity of productions so ex~ct as to include identity of species, or even genera. Bestdes the various isolated regions here enumerated, there are some others indicated by naturalists as exhibiting a vegetation equally peculiar. Some of these are isolated by moun· tains or the interposition of sandy wastes. For example, the temperate region of the elder continent is divided about the centre of Asia, and the east of that line is diffe .. ent from the west. So also is the same region divided in North America by the Rocky Mountains. Abyssinia anti Nubia ·constitute another distinct botanical region. De Candolle enumerates in all twenty well-tnarked portion~ of the earth's surface, which are peculiar with respect to vegetation; a number which would be greatly increased, if remote islands and isolated mountain ranges were to be included. When we come to the zoology, we find precisely similar results, excepting that man (with, perhaps, some of the less conspicuous forms of being) is universal, and tha: several tribes, as the bear and dog, appear to have passed by the land connexion from the arctic regions of the eastern to those of the western hernisphere. " With these ex· ceptions," says Dr. Prichard, " and w~thout an! ot~enz~ • ANIMATED NATURE • . 131 as far as zoologi~al.r~sea1·ches have yet gone, it n ~y be ass~rted that no Indi v1d_ual speeies are common to distant regwns. In parall~l climates, analogous species replace each o.ther; so~etimes, but not frequently, the same g~nus 1~ found In t~o separate continents; but the spe· CI~s winch are !lahves of one region, are not identical w~th corresponding races indigenous in the opposite hemisphere. "A. similar ;result a~·ises when we compare the three great Int:rtro~ICal reg.wns, as w~ll as the extreme spaces of the th~ee great continents, which advance into the tempe! ·,ate climates ~f the so~th_ern hemisphere. ~hus, the tribes of s11p.ue, (monkeys,) of the doO' and cat k~nds, of pachyderms, inclu~ing elephants, tapirs: rhinocProses, hog:s, of bats, of saunan and ophidian reptiles as w~ll as of bu·ds and other terrene animals· are all diffe~ rent In the three great continents. In the lower departments of the mamrnif'erous family we find that the bruta or edentata .(sloths, armadillos, &c.) of Africa, are diffe~ r~n tly orga~nzed frorn ~hose of America, and these again f1 orn the tnbe_s found In the Maylayan archipelago and Terra Australis."* It d~es not appe~r that .the diversity between the simi! ar . re~10ns of Afrtea, A~m, and America, is occasioned In all Instances. by any disqualification of these countries to support precisely the same gene~·a or species. The ox, horse, goat, &c., of the elder continent have driven and extended.themselves in the ne\v; and many of the indigenous ~nbes .of Am~rica would no doubt flourish in corresponding chmates 1n Europe, Asia, and Africa. It has h~wever, been remarked by naturalists unacquainted With th~ Macleay system, that the larger and more powerfu~ animals of their respective orders belong to the elder continent, and t~at t_hus the animals of America, unlike the features of 1nan1!flate nature, appear to be upon a small scale. . The swiftest and most agile animals, and a I~rge proportion of th?se most useful to man, are also na .. t1ves of the eldei~ continent. On the other hand, the bulk of the edentata? a group remarkable for defects and meanness ?f organ1zatt?n, are American. The zoology of Ame~IC~,may be said, upon the whole, to recede from that of As1a, and perhaps In a greater deo-ree "adds Dr p ·• ehard, "from that of Africa." A mugh g~eater rece.ssi~~ • Researches, 4th edition, i. 95. |