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the northern hemisphere. Thus the African Region is the more special: ized division, only a small portion of the tropical element in the Indian Region, through which it is differentiated from the great Europæo. Asiatic Temperate Region, being unrepresented in the African, while the African has three times as many peculiar families as the Indian.* Aš shown by the subjoined table, thirty of the fifty Indo-African families have a wide extralimital distribution, not less than one fourth being emphatically cosmopolitan,
Families of Mammals represented in the Indo-African Realm, arranged to show (approxi
mately) their distribution.
"The Trichechidæ (= Manatidae) occur in Africa but not in India, but are found also in the warmer parts of America.
* Wholly restricted to the Indian Region.
1 0f wide extralimital range. | Mainly restricted to the Indian Region.
& Found also in Intertropical America. il Chiefly African
African Region.--The African Region, as here recognized, is nearly equivalent to Mr. Wallace's “ Ethiopian Region", with the exclusion
* Mr. Wallace has arrived at rather different conclusions respecting the specialization of the African Region, since be considers its specialization due wholly to the peculiar forms developed in Madagascar. Deducting these--for he considers Madagascar and its neighboring islands as forming a “subregion'merely of the “Palæotropical”– he believes would leave, in respect to specialization, the African and Indian Regions "nearly equal". In this comparison, however, I wholly exclude the Madagascan of « Lemurian” fauna, and still find Africa a considerably more specialized region.
Ore set of bis “ Lemurian Subregion". Its northern boundary will be prothe Ik visionally considered as the northern mean annual of 700 F. Eure Astbus limited, the greater part of the Arabian Peninsula and the southWbik ern portion of the Great Salara belong to it. But just how much of the lian. latter belongs here, and how much to the Mediterranean Region, cannot n fan. at present be readily determined. As already noticed, it consists largely irth le of transitional ground, and is as yet quite imperfectly known. It is to
some extent, doubtless, also a barrier region; but that it is by no means au impassable obstacle is sufficiently sbown by the large number of generic types of mammals that extend from tbe Indian Region as far southward even as the Cape of Good Hope. Even if it were an insurmountable barrier, the comparatively humid and fertile eastern coast border
would afford a sufficient highway of intercommunication between Trop. . ridec ical Asia and Tropical Africa, and the community of life of the two
regious shows that for long ages there has been this open way of interchange.
The African Region, considering its great extent aud its tropical climate, is to a great degree zoölogically a unit, yet it is by no means homogeneous. At least, three subdivisions may be recognized, each of which is characterized by many peculiar genera. These subregions hare already been characterized by Mr. Wallace under the names of Eastern, Western, and Scuthern. The Western (West African Province) consists of the humid, heavily wooded region of the west coast, extend. ing to a considerable, but at present not definitely determinable, dis. tance into the interior, but probably with boundaries nearly as drawn by Mr. Wallace.* The Eastern (East African Province) includes the remainder of Intertropical Africa, while to the Southern (South African Province) belongs the southern extratropical portion of the continent.
Of these divisions, the Eastern contains the greatest number of genera, as it likewise contains by far the greatest area; but it is the least spe. cialized, only tuo fifteenths of its genera being peculiar to it, while of the genera of each of the other regions about one-fourth are peculiar. Nearly one-half (about forty-four per cent.) of the genera of the Eastern Prov. ince have a more or less general distribution over the whole African Region, while only a little more than a third (thirty-three to thirty-eight per cent.) of the genera of the other province bave a similarly wide range.
A much larger proportion of Indian genera are represented in the Eastern and Southern Provinces than in the Western. This difference is due to obvious conditions, the fertile belt of the Nile district and adjoining coast forming an easy way of intercommunication between the
* The conclusions and details here presented were worked out independently and de novo by the present writer. That they agree so closely with the views and results attained by Mr. Wallace, so far as Africa south of the Great Desert is concerned, is to me a source of gratification. In order to avoid unconscious bias I purposely avoided a detailed study of Mr. Wallace's writings on this subject till my own results were written ont, and on then comparing my own conclusions with those reached by Mr. Wallace, became for the first time aware of their close agreement.
two former not equally open to the Western Province. The Eastern and Southern Provinces further resemble each other in consisting largely of grassy plains, and in being, par excellence, the land of Antelopes. On the other band, the Western Province, in consequence of its moist climate and dense forests, is the metropolis of the African Quadrumanes, to wbich region no less than six genera are restricted, and where all but one are represented, while only four occur in the Eastern, and merely a few outlying species reach the Southern. Hence the Eastern and Southern Provinces are far more closely allied than is either with the Western. · Eastern Province.--The East African Province or “Subregion" includes, as claimed by Mr. Wallace, not only East Africa proper, but also a considerable portion of the Great Sabara and the wbole of the northern portion of Tropical South Africa, thus bounding the Western Province on three sides. In other words, it not only includes East Africa and Southern Arabia, but all of Tropical Africa, except the western portion, situated (speaking generally) between latitude 150 north and latitude about 220 south. As is well known, it consists mainly of a moderately elerated plateau, rising, in Abyssinia, into lofty mountains. It is generally an open region, “covered with a vegetation of high grasses or thorny shrubs, with scattered trees and isolated patches of forest in favorable situations. The only parts where extensive continuous forests occur are on the eastern and western slopes of the great Abys. sinian plateau, and on the Mozambique coast from Zanzibar to Sofala."* It is worthy of note that the species peculiar to the province occur almost exclusively in Mozambique, or in Abyssinia and adjoining portions of Northeast Africa, a few extending into the Arabian Peninsula.
Of the ninety genera occurring in this province, ten, which are almost cosmopolite, may be considered as baving too wide a range to possess any special significance. Of the remaining eighty, about one-fourth are found also in the Indian Region, leaving three-fourths (thirty-nine) as peculiarly African. Of these, twelve only are restricted to the Eastern Province, sixteen being common to the Southern Province, and teu to the Western. The subjoined tabular list indicates approximately the distribution of the genera of the Eastern Province.
* Wallace, Geogr. Dist. Anim., vol. I, p. 250.
* Restricted to Abyssinia and Northeast Africa.
t Restricted to Mozambique. See Rolleston, Trans. Linn. Soc. Lond., 2d ser., Zoöl., vol. 1, pp. 256, 257, 1877.
The Southern Province. The South African Prorince consists of only that small portion of the continent lying south of the Southern Tropic, and is bence situated wholly within the southern warm-temperate zone. In consequence of its configuration, its limited extension, and its geographical position in relation to Intertropical Africa, it could scarcely be expected to form more than an appendage of the inter. tropical zone, and such it proves really to be. Its area is equal to only about one-tenth of that of the Eastern Province, yet it has eight-ninths as many genera, fully two-thirds of which are common to the two. It hence presents to only a limited degree the features of a strictly temperate fauna, and these become prominent only over the narrow belt of country south of the mountain ranges forming the northern boundary of Cape Colony and Caffraria; but here even there is a strong invasion of essentially tropical forms.
In general facies it differs little zoölogically from the Eastern Province, of which it is merely a somewhat modified continuation. From its semi-temperate character it is less rich in Quadrumanes, but many other properly tropical types range nearly or quite to its southern bor. der. It has, however, about one-fourth more peculiar genera, divided about equally, and mainly between Carnivores and Rodents, four oply being Antelopes, and one only (Chrysochloris) an Insectivore. Of the twenty-four genera common also to the Indian Region, one-third are Chiropters. The remaining genera are, with very few exceptions, such as occur also in the Eastern Province, only three or four being common to the Southern and Western Provinces that do not also occur in the Eastern.
Of the eighty-two genera below enumerated as occurring in the Southern Province, a considerable portion are restricted to its southern half, while many others extend only over its northern portions. A few others, wbile mainly restricted to this region, and eminently characteristic of it, also extend somewhat into the Eastern Province.
The Western Province. As already stated, the Western Province differs greatly in respect to its physical characteristics from either of the other provinces of the African Region, and has, in consequence, a correspondingly specialized mammalian fanpa. It resembles the In. dian Region in its hot, damp climate and dense forests. And its fauna, though distinguished by many peculier genera, is also, in respect to its general facies, more like that of the Indian Region than is the fauna of any other portion of the African Region. It is similarly rich in the higher Quadrumanes and poor in Antelopes, while it shares with the