Imágenes de páginas
PDF
EPUB

(3) One genus (Geogale) of the family Potamogalidm (shared with the West African Sub-region) and six genera making the whole of the family CenteticUe, among the Insectivores.

(4) One genus (Chiromys), alone forming the family Chiromyidm, and ten genera of the family LemuricUe, out of a total of fifteen generally recognized.

Almost equally important is the absence of the following groups:—

(1) The orders Edentata and Ungidata (except Potamochoerus).

(2) The families Sciv/ridm (Squirrels), Spalacidaz (Blind Moles), OctodonticUe, HystricidM (Porcupines), and Leporidm (Hares), among the rodents.

(3) The families Felidm (Cats), Canidm (Dogs), and Mustelidm (Weasels), among the Carnivora.

(4) The Primates, other than the lemurs.

The following table shows the number of genera of each order represented in the Malagasy Sub-region and their distribution:—

[table]

[N.B.—The "Endemic" genera are those confined to the Malagasy Sub-region; the "African" genera are those common to Madagascar and the mainland of Africa; and the "Cosmopolitan" genera are those which range beyond the limits of the Ethiopian Region.]

Section V.—The West African Sub-region

The West African Sub-region, as defined above, does not contain nearly so large a proportion of peculiar genera as the Malagasy Sub-region. At the same time, twelve out of a total of eighty genera of mammals that are found within its limits are not met with elsewhere. Moreover, we notice that, as a general rule, the genera inhabiting other parts of Africa are here replaced by distinct species.

The Edentata are represented by one genus, Manis, the Scaly Ant-eater. Of the four known African species three are confined to this Sub-region.

Of the Ungulates only one genus is endemic. This is Hyomoschus, a very curious aquatic form, which, together with an allied genus found only in the Oriental Region, forms a peculiar Family (Tragulidm) distantly allied to the deer (Cervidm). Many of the genera of Ungulates, however, are here represented by peculiar species. Instances of this are the Liberian Hippopotamus (Hippopotamus liberiensis), the Red River-hog (Potamoch&rus penicillatus), the West African Eland (Oreas derbianus), a peculiar species of wild ox (Bos pumilus), and several species of Rockconey (Hyrax).

The Rodents do not present any features of special interest, the only peculiar genera being Deomys (allied to Mus), recently obtained from the Congo district; and the Brush-tailed Porcupine (Atherura), of which one species is found only in this Sub-region, and the other two are confined to South-East Asia. Four out of the five known species of the peculiar Rodent-genus Anomalurus, already referred to, are also confined to the West African Sub-region.

Turning now to the Carnivores, there are found in the West African Sub-region only, two remarkable genera, Poiana and Nandinia. Of these the former is closely allied to the genus Prionodon, a beautifully marked civetlike little animal of the Oriental Region, and the latter is akin to the Palm-civets (Paradoxv/ms), also found in the Oriental Region, but not in Africa.

There is only one genus of the Insectivora confined 'to this Region (Potamogale), already alluded to as being probably allied to the Madagascan Geogale. This much modified form is one of the few members of the Insectivora that has adopted aquatic habits. It is, for a member of the order, of considerable size.

The Bats of West Africa, as is usually the case in every land, belong mostly to widespread forms. Out of sixteen genera only two, each containing a single species, are confined to this Sub-region, while a third (Epomophorus) has not been found outside Africa. These three genera all belong to the family PteropodicUe, which contains the large fruit-eating bats. A few species of Lemurs still survive in the forests of the West African Sub-region. They belong to two genera, neither of which is represented in Madagascar. Of these, one (Galago) is also found in the other parts of Africa; the other (Perodicticus), containing two species, is met with only in the West African Subregion.

The forests of West Africa are plentifully supplied with Monkeys. Most of these belong to the genus Cercopithecus, of which, out of about forty species, thirty are met with in West Africa. Another enus, Cercocebus, contains four species, all confined to this Subregion.

Finally, it is only in these pathless and luxuriant jungles that two man-like apes, the Chimpanzee and the Gorilla, are to be met with. The Gorilla seems to be confined to the Gaboon district, but the Chimpanzee extends all over the Congo basin nearly up to the shores of Tanganyika.

These two, together with the Orangs and the Gibbons of the Oriental Region, make up the family Simiidm, which in structure is the most closely allied to Man of all the Monkeys.

On comparing the West African Fauna with that of the rest of Africa, it will be seen that it is characterized by the exclusive presence of the following forms:—

1. Hyomoschus (the Water-chevrotain), which, together with Tragulus of the Oriental Region, forms the family of Tragididm of the Ungulata.

2. Two genera (Malacomys and Deomys) of the family Mvmdm, and Atherura (Brush-tailed porcupine), found elsewhere only in the Oriental Region, among the rodents.

3. Two genera (Poiana and Nandinia) of the family Viverridm, among the Carnivora.

4. Potamogale, among the Insectivora.

5. Two genera of fruit-eating bats (Liponyx and Trygonycteris).

6. Perodicticus, a genus of Lemurs, and Cercocebus, and Anthropopithecus, among the higher Monkeys.

The West African Region is further characterized by the absence of the following families, well represented in other parts of Africa: Orycteropodidm (Aard-vark), Grirafftdm (Giraffes), Equidm (Zebras and Wild Asses), Rhinocerotidm (Rhinoceroses), and Leporidm (Hares).

The following table shows the approximate number of genera of the West African Sub-region in each order and their distribution:—

[table]

Section VI.—The Cape Sub-region

This Sub-region, when extended so as to include the whole country as far north as Angola on the west, and up to the Tana river on the east, is on the whole, after the Malagasy, the most distinct of the four Sub-regions, since it possesses nineteen endemic genera out of a total of ninetyone. Furthermore, its area exhibits a greater range of temperature and humidity than the other Sub-regions, for, while in Natal and Mozambique tropical forest-conditions prevail, giving the fauna a certain resemblance to that of West Africa, in Cape Colony itself a temperate and fairly dry climate is found. Again, in Namaqua-land, to the north-west of Cape Colony, we meet with an open, dry, hot, desert country, the conditions of which closely approximate to those of the Saharan Sub-region. The distinctness of this Sub-region, apart from the mammals, is strongly marked by a very remarkable Flora, as well as by the exclusive possession of many forms among the other orders and classes of the animal kingdom. Among the Edentata,

H

« AnteriorContinuar »