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thirty-five species, to which family, also, the African and two of the Oriental genera are generally assigned ; and (6)
the Chiromyidæ. The Indrises (Indrisina) form a distinct sub-family of Lemuride with three genera, all restricted to Madagascar (see Fig. 21, p. 105). The typical Lemurs (Lemuridæ) are also only found in this island (see Fig. 22, p. 106).
The second family of the Lemurine Order (Chiromyide) contains only a single genus and species, the extremely
anomalous Aye-aye, discovered by the traveller Sonnerat in 1780 (see Fig. 23). There are generally examples of this curious animal in the Zoological Society's gardens in London, but, unless especially aroused, they are seldom seen by daylight. Their chief peculiarity is the long, thin, ghost-like middle finger, with which they have been supposed to extract wood-boring insects from their burrows, although their chief food in captivity certainly consists of succulent juices.
Of the extinct mammal-fauna of Madagascar we know as yet too little. Dr. Forsyth-Major (4) has lately described a large lemur (Megaladapis) differing considerably from those now inhabiting the island; while remains of two small Lemurs and of two small species of Hippopotamus have been also met with. These remains, together with the bones of a large flightless bird (Æpyornis), apparently allied to other Ratite birds, are of a comparatively recent period.
On the whole, however, we cannot but presume that Madagascar originally obtained its animal life from the mainland of Africa. The striking differences between the present faunas of Africa proper and Madagascar are doubtless due to the fact that the great bulk of the existing African fauna is of comparatively modern origin, and came from the Northern continent at the end of the Miocene or the beginning of the Pliocene times, whereas Madagascar was cut off from Africa before this eruption of Northern forms took place. Madagascar, therefore, appears to contain a sample of the ancient Ethiopian fauna, which has been almost exterminated on the mainland, but has survived here under the protection afforded by its separation from the adjacent continent. The fauna of the Malagasy Sub-region may be summarized by the exclusive possession of
(1) Seven genera of the family Muridæ, among the Rodents.
(2) Six genera of the family Viverride, among the Carnivores.
(3) One genus (Geogale) of the family Potamogalidæ (shared with the West African Sub-region) and six genera making the whole of the family Centetidæ, among the Insectivores.
(4) One genus (Chiromys), alone forming the family Chiromyidæ, and ten genera of the family Lemuridæ, out of a total of fifteen generally recognized.
Almost equally important is the absence of the following groups :
(1) The orders Edentata and Ungulata (except Potamochoerus).
(2) The families Sciuridæ (Squirrels), Spalacidæ (Blind Moles), Octodontidæ, Hystricidæ (Porcupines), and Leporidæ (Hares), among the rodents.
(3) The families Felidæ (Cats), Canidæ (Dogs), and Mustelide (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:
[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 (Tragulidæ) distantly allied to the deer (Cervidæ). 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 (Potamochoerus 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,