{253}_Mammalia._--This region has 9 peculiar families of mammalia. Chiromyidæ (containing the aye-aye); Potamogalidæ and Chrysochloridæ (Insectivora); Cryptoproctidæ and Protelidae (Carnivora); Hippopotamidæ and Camelopardalidæ (Ungulata); and Orycteropodidæ (Edentata). Besides these it possesses 7 peculiar genera of apes, _Troglodytes_, _Colobus_, _Myiopithecus_, _Cercopithecus_, _Cercocebus_, _Theropithecus_, and _Cynocephalus_; 2 sub-families of lemurs containing 6 genera, confined to Madagascar, with 3 genera of two other sub-families confined to the continent; of Insectivora a family, Centetidæ, with 5 genera, peculiar to Madagascar, and the genera _Petrodromus_ and _Rhynchocyon_ belonging to the Macroscelididæ, or elephant-shrews, restricted to the continent; numerous peculiar genera or sub-genera of civets; _Lycaon_ and _Megalotis_, remarkable genera of Canidæ; _Ictonyx_, the zorilla, a genus allied to the weasels; 13 peculiar genera of Muridæ; _Pectinator_, a genus of the South American family Octodontidæ; and 2 genera of the South American Echimyidæ or spiny rats. Of abundant and characteristic groups it possesses _Macroscelides_, _Felis_, _Hyæna_, _Hyrax_, _Rhinoceros_, and _Elephas_, as well as several species of zebra and a great variety of antelopes. The great speciality indicated by these numerous peculiar families and genera, is still farther increased by the absence of certain groups dominant in the Old-World continent, an absence which we can only account for by the persistence, through long epochs, of barriers isolating the greater part of Africa from the rest of the world. These groups are, Ursidæ, the bears; Talpidæ the moles; Camelidæ, the camels; Cervidæ, the deer; Caprinæ, the goats and sheep; and the genera _Bos_ (wild ox); and _Sus_ (wild boar). Combining these striking deficiencies, with the no less striking peculiarities above enumerated, it seems hardly possible to have a region more sharply divided from the rest of the globe than this is, by its whole assemblage of mammalia.