266 ZOOLOGICAL GEOGRAPHY. [part hi. 



Anomalurus, shows that this island has probably once been united 

 to the continent. 



Prince's Island, situated about 100 miles from the coast, has 

 no mammals, but between 30 and 40 species of birds. Of these 

 7 are peculiar species, viz., Zosterops Jicedulina, Cuphopterus dohrni 

 (a peculiar genus of Sylviidse), Symplectes princeps, Crithagra 

 rufilata, Columba chlorophcea, Peristera principalis, and Strix 

 thomensis. 



In the Island of St. Thomas, situated on the equator about 150 

 miles from the coast, there are 6 peculiar species out of 30 known 

 birds, viz., Scops leucopsis, Zostcrops lugubris, Turdus olivaceo- 

 fuscus, Oriolus crassirostris, Symplectes sancti-thomoe and Aplopelia 

 simplex ; also Strix thomensis in common with Prince's Island. 

 The remainder are all found on the adjacent coasts. It is re- 

 markable that in Prince's Island there are no birds of prey, any 

 that appear being driven off by the parrots (Psittacus erithacus) 

 that abound there ; whereas in St. Thomas and Fernando Po 

 they are plentiful. 



III. South-African Sub-region. 



This is the most peculiar and interesting part of Africa, but 

 owing to the absence of existing barriers its limits cannot be 

 well defined. The typical portion of it hardly contains more 

 than the narrow strip of territory limited by the mountain range 

 which forms the boundary of the Cape Colony and Natal, while 

 in a wider sense it may be extended to include Mozambique. It 

 may perhaps be best characterised as bounded by the Kalahari 

 desert and the Limpopo river. It is in the more limited district 

 of the extreme south, that the wonderful Cape flora alone exists. 

 Here are more genera and species, and more peculiar types of 

 plants congregated together, than in any other part of the globe 

 of equal extent. There are indications of a somewhat similar 

 richness and specialization in the zoology of this country ; but 

 animals are so much less closely dependent on soil and climate, 

 that much of the original peculiarity has been obliterated, by 

 long continued interchange of species with so vast an area as 



