GEOGRAPHICAL DISTRIBUTION 345 



forms are the result of interbreeding between the extremes is 

 to begin at the wrong end, and virtually to mistake cause for 

 effect.^ In reality there is no need to make any assumption whatever. 

 It is far better, certainly at the present time, to stick to the plain 

 facts of each case, so far as we can acquaint ourselves "vvith them, 

 and there is every appearance of each case having to be treated 

 upon its own merits. But opportimities for generalization will, of 

 course, come at last, and meanwhile we shall possibly not be far 

 wrong in expecting, as one result of the facts already kno"\vn and 

 undoubtedly to be multiplied by increased observation, an elucida- 

 tion of what has seemed to so many an insoluble puzzle — the 

 repetition, so to speak, of similar forms in "Western Europe and in 

 Eastern Asia without their appearance in the intermediate terri- 

 tory, or cases of, to use another expression, " interrupted distribu- 

 tion " — be the interruption as in that of Cyanopica, already 

 mentioned, absolute, or modified more or less as in so many other 

 instances. 



V. The Ethiopian Region is by no means easily divided. In 

 treating of it in 1875 {Encyclop. Brit. ed. 9, iii. pp. 757-760), the 

 present writer followed in the main the guidance kindly afforded 

 him by Dr. Sharpe, whose knowledge of its Avifauna is hardly, if at 

 all, exceeded by that of any other ornithologist, and recognized five 

 Subregions. The progress of geographical discovery, which has of 

 late years laid open so much of the wilds of Central Africa, has 

 shewn a much greater homogeneity than was before expected in the 

 Faima of the several parts of that continent, though it is true that 

 the explorers of its interior have in few cases had any zoological 

 knowledge or even taste, and that to at least one of the most cele- 

 brated of them scientific research of any kind is repellent. It must 

 also be remembered that nearly all of those few zoological explorers 

 have forfeited their life ^ in their zeal for investigation, and, with 

 the notable exception of Emin Pasha, scarcely one has survived to 

 carry on his observations or to make collections for any length of 

 time. Consequently the vast area of Equatorial Africa, and the 

 districts immediately conterminous, are ornithologically almost 

 unknown. Meanwhile we do know that nearly all the most 



^ The seeming inability to gi-asp this position detracts greatly from the 

 value of nearly all that Mr. Seebohm has written on the geographical distribu- 

 tion of birds in the Palsearctic Subregion and elsewhere, leading him to con- 

 clusions of the most erroneous kind, which have been uncritically accepted by 

 several other writers. 



^ It would be impossible here to name even the natm-alists who from Mungo 

 Park downwards have fallen victims to African exploration ; yet, in an ornitho- 

 logical work, William Alexander Forbes must be especially mentioned, as it was 

 the pure love of ornithology that led him i;p the Niger, where he succumbed to 

 fever in the very prime of life. 



