DISTRIBUTION OF ANIMALS. 312 DISTRIBUTION OF ANIMALS. tion on lliij^ sul>jc<.t in the mtuiuI vuIuiik' of liis Oriyiii •-/ .'•ptcics (London, ISS'2). It will lie soun that the varj-ing abilities among the ilillVrrnt jiioups of animals would make their distribution equally dillerent one from the other. Salt water is a poison to larval amphibians, while birds may lly aeross more than 1000 miles of sea spate. Mammals may run about rapidly, while the reptiles and small invertebrate erea- tures must ereep slowly or not at all. Kinally, marine animals ot'eu])y an area and medium en- tirely dillerent from that held by terrestrial ani- mals. Tlu'se variations must be borne in mind in attempting to reduee to sehenic and system the vastly diverse phenomena of zoogeography. Faixal Kecioxs. Heretofore we have been considering only the dispersion and restrietion of a speeies. But as a rule several kindred eo- exist in any given area, and these usually differ in their range, while oceasionally a speeies of the same genus is to be found somewhere else, entirely disconnected from its fellows. This shows that the geii^rrapliiial area covered by a genus is greater than that of a species: and, carrying the same inquiry further, it appears true of families, orders, and classes. The larger the group in the scheme of classification the wider its geograiihical area. To ascertain and record the spread, past and present, of the groups of animals is the business of zoiigcograpliy. The earlier students drew tip a map in which they con- fidently set apart a series of realms, jirovinces, and subprovinc'cs. A vast amount of such in- formation had been tabulated tiy Sdatcr, Dar- win, Schmarda, Murray, and others previously to the publication, in 1876. of .Mfred Kusscll Wal- lace's monumental work on the subject. Wallace, following Selater (18.)"), divided the globe into six grand 'regions,' each characterized by groups of animals absent from, or very scantily repre- sented in, any other. These were: I'aUiirvlic Uffiioii. — Kurope, Africa north of the Sahara, and .sia north of the Himalayas. Oriental llciiioii. — India, Malaya, southern China. Sumatra, .Java, Borneo, the Philippines, and included islands. .1 iislralian Keflioii. — .ustralia and the islands north of it from Celebes eastward. New Zealand and the South Sea archipelagoes. This was di- vided from the Oriental region by Wallace's line — a name gracefully given by Huxley in l.S(«S to the /oiigeographical demarcation discovered by A. P.. Wallace (Ihi.s, London. 18.')!1: I'rovicilinfis Zoological Society, London, 18t>:!: Malay Arrhi- pelayo, l.ondon and New York, 1869), which passes along the narrow straits between the Philippine and Sulu islands, and southward between Celebes and Borneo, Lombok and Java. He found the birds and mammals strik- ingly ditTerent on opposite sides of this line of deep channels. "The great contrast be- tween the two divisions of the archipelago," he informs us, "is nowhere so abruptly exhibited as in passing from the island of Bali to that of Lombok, where the two regions are in closest proximity. . . . The strait is here 1.^ miles wide, so that we may pass in two hours from one great division of the earth to another. dilTer- ing as essentially in their animal life as Europe does fr<im .America If we travel from .lava or Borneo to Celebes or the Moluccas, the dif- ference is still more striking. In the first the forests abound in monkeys of many kinds, wild- cats, deer, ciil~, and ollcr~. ;ind nuiiurous va- rieties of squirrels are constantly met with. In the latter none of these occur, but the i)icliciisilc- tailed cuscus is aliuo.st the only terrestrial mam- mal seen. . , . The birds, which are most abundant in the western islands, are wo()d])eek- ers, barbets, trrjons, fruit-thrushes, and leaf- thrushes: they are seiMi daily and form the great ornitliulogical feature of the country. In the eastern islands these are absolutely unknown, honeysuikcrs and small lories biiug the must com- mon birds: so that the naturalist feels himself in a new world." I'akotropical (or Ethiopinn) Region. — Africa south of the Sahara, and Madagascar. Xcarctic Region. — North America and the ele- vated central region of Mexico. yeolropiral Region. — South America, Central America, and the West Indies. Kach of these regions was divided into four sub- regions or 'provinces.' In .frica. Cape Colony and the southeast coast formed a i)rovince, the Congo and Niger basins together another, Mada- gascar and the Mascarene Islands a third, and all the rest of the continent south of the Sahara a fourth. In North America, all Canada north of Lake Huron and the Saskatchewan was one prov- ince, the eastern United States as far as the central dry plains formed a second, the Rocky .Mountain country and "great basin' a third, and the Pacilie Coast the fourth. And so on. For the faunal characteristics of each of these regions, sec the articles luider their names: also JloLAKtTic Regio.n : Neoc.ka; Notog.ka. Arctog.ea M) Notog.ea. The apportionment above sketched has proved too artificial. The pro])riety of separating North America from Europe and Asia was soon disputed, and they were united by various authorities in a single circumpolar region called llolarctie (or Peri- arctic). The equatorial countries, mostly sepa- rated by oceans, cannot lie so easily combined, and for some time the only serious change in the classic arrangement was the erecticm of the New Zealand group from sticondan- to ])rimary rank. Much is to be said in favor of this movement, but it seems not to be generally acceptable. As knowledge of both the living and fossil ani- mals of the southern continents and islands has increased, and criteria have become largely avail- able outside of the groups of birds and mammals up(m which earlier conclusions were mainly based, it becomes more and more apparent that even these regional distinctions are vague. The best o|)inion at the opening of the twentieth century, following Huxley (1868), held that only two prime regions might be recognized in zoogeog- raphy — .irctogwa, a northern world, and .Yofo- gaii, a southern world. These names, however, are not precisely descriptive. Arctog.Ta includes not only the whole Northern lleniisphi-rc. but also Paleiitropica (.frica. India, ami llie Ea-t Indies as far as Wallace's line). Notogu'a is formed of South and Central America and .Australasia. Within these primary realms the old subdivi- sions seem to hold pretty well, except that North .merica docs not seem se])arable from Eurasia, both now forming the single Holarctic Region (q.v. ) of recent students. Lesser subdivisions must be determined inde- iwndently. if at all, for each group under study. Nor have even the largest zo<igeographical divi- sions liard and fast botindnries. They overlap
