The geographical distribution of animals, with a study of the relations ...

266 ZOOLOGICAL GEOGRAPHY. [part hi.Anomalurus, shows that this island has probably once been unitedto the continent.Prince's Island, situated about 100 miles from the coast, hasno mammals, but between 30 and 40 species of birds. Of- these7 are peculiar species ,\iz., Zostcrojjs Jiccdulina, Cupliopterus dohmi(a peculiar genus of Sylviidse), Sympledes princeps, Crithagrarvfilata, Columba chlorophosa, Peristera principalis, and Strixthomensis.In the Island of St. Thomas, situated on the equator about 150miles from the coast, there are 6 peculiar species out of 30 knownbirds, viz., Scops leucopsis, Zosterops lugubris, Turdus olivaceofuscus,Oriolus crassirostris, Sympledes sandi-thomce and Aplopcliasimplex ; also Strix thomensis in common with Prince's Island.The remainder are all found on the adjacent coasts. It is remarkablethat in Prince'sIsland there are no birds of prey, anythat appear being driven off by the parrots (Psittams erithacus)that abound there ; whereas in St. Thomas and Fernando Pothey are plentiful.III.South-African Sub-region.This is the most peculiar and interesting part of Africa, butowing to the absence of existing barriers its limits cannot bewell defined. The typical portion of it hardly contains morethan the narrow strip of territory limited by the mountain rangewhich forms the boundary of the Cape Colony and Natal, whilein a wider sense it may be extended to include Mozambique. Itmay perhaps be best characterised as bounded by the Kalaharidesert and the Limpopo river. It is in the more limited districtof the extreme south, that the wonderful Cape flora alone exists.Here are more genera and species, and more peculiar types ofplants congregated together, than in any other part of the globeof equal extent. There are indications of a somewhat similarrichness and specialization in the zoology of this country; butanimals are so much less closely dependent on soil and climate,that much of the original peculiarity has been obliterated, bylong continued interchange of species with so vast an area as