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 “Cafirarian”! Province. In 1884 Dr. Sharpe, when 
writing the preface to the second edition of Mr. Layard’s Birds 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, however 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 Region 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—Buphagidx, Eurycerotidx, Philepittidx, 
Musophagidz, Rhinopomastidx, Leptosomidx, Coludx, Serpentarvidx, and 
_ Struthiomdx—are peculiar; but it is a singular fact that only the 
first three of them belong to the Order Passeres, 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 
differentiated to a degree that is very extraordinary, will presently 
be mentioned. 
1 Acain following Blyth (Coc. cit.) 
2 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. 
3 Should its delimitation be ever effected, it will probably be done by taking 
tognizance 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 Manidx, and the non-occurrence of any representative of the 
Ganoids among Fishes in the more southern rivers of Africa. 
