GEOGRAPHICAL DISTRIBUTION 347 



lying still further south and extending to the Cape of Good Hope. 

 However, of the species which inhabit part of this territory, the 

 Cape Colony and some of its adjoining lands, we may say that our 

 acquaintance is as good as we have with the Avifauna of almost 

 any country outside of Europe and North America, and though it 

 has some clear characteristics at its extremity, these melt away 

 gradually towards the north and seem finally to be lost. Still their 

 existence ought to be taken into account, and therefore we may 

 recognize a " Caffrarian " ^ Province. In 1884 Dr. Sharpe, when 

 writing the preface to the second edition of Mr. Layard's Bird.s of 

 South Africa, considered the " natural limits " of what he termed 

 the " South African Subregion " (which is practically equal to the 

 CafFrarian Province just mentioned) to be the Zambesi River on 

 the east and the Quanza or Coanza on the west. Now it ought to 

 be obvious that no river (however wide) can form the "natural 

 limit" of any zoological area,^ and indeed the cases are rare 

 in which a river limits the range of any species of land-animal. 

 This proposed boundary, therefore, hoAvever convenient for some 

 purposes, is as artificial and arbitrary as that of the 28th parallel 

 of south latitude adopted by Mr. Layard in 1867 for the first edition 

 of his work, and indeed it is pretty evident that no boundary 

 is yet to be laid down, even if one is ever to be found. ^ 



So large a portion of the Ethiopian Eegion lies between the 

 Tropics that no surprise need be expressed at the richness of its 

 Fauna relatively to that of the Holarctic last considered. Between 

 50 and 60 Families of Land-birds alone are found within its 

 limits, and of them at least 9 — Buphagidie, Eiirycerotidx, Fhilepittidse, 

 Musophagidge, Rhinopomastidse, Leptosomidse, Coliidm, Serpentariidse, and 

 SirutJiionidm — are peculiar ; but it is a singular fact that only the 

 first three of them belong to the Order Fasseres, a proportion which 

 is not maintained in any other Tropical Region. The number of 

 peculiar genera is too great for them to be named here ; some of 

 the most remarkable, however, especially of those belonging to the 

 insular or Madagascarian Subregion, where Bird-life has been 

 diflferentiated to a degree that is very extraordinary, will presently 

 be mentioned. 



^ Again following Blyth {loc. cit.) 



^ Unless indeed the river be a channel left by the silting up of an inland sea, 

 as is said to be the case with the lower Amazon. 



^ Should its delimitation be ever effected, it will probably be done by taking 

 cognizance of other Classes than that of Birds. The extraordinary diversity of 

 forms shewn by certain groups of Mammals, and especially of the hollow-horned 

 Ruminants, generally known as Antelopes, towards the southern extremity of 

 the African continent can hardly fail to be of use in this investigation, coupled 

 also with the absence of so well-marked and apparently so ancient a Family of 

 Edentates as the Ifanidx, and the non-occurrence of any representative of the 

 Ganoids among Fishes in the more southern rivers of Africa. 



