CllIROPTEKAV NOTES IO 



guiiieends) occupying- the Congo ValJey, from whicli it has spread 

 eastwards, south westwards, and northwestwards; tlie other (H. c. 

 caffer + ieplirus) occujn-ing the rest of Africa, the extreme 

 south and the ^lediterranean coast region excepted. This being so. 

 it might be questioned, wdiether it would not be better, from a 

 leclniical point of view, to treat these two principal forms as 

 distinct « species », viz. H. caffer (subdivided into H. caffer caffer 

 and H. caffer tephrus) and H. centralis (subdivided into H. cen- 

 I ralis centralis imi\H. centralis guineensis); it would have the 

 <)b\ious advantage of expressing, ])y the very technical names, the 

 1rue phylogeny of the races, whereas, when we put all the races 

 down as « subspecies » of H. caffer, our nomenclature obscures 

 tlieir jihylogenetic interrelations, in so far as then the technical 

 names of the four races easily convey the idea that they are of 

 eipial « value » (i. e. (Mpially distinct from each other), which 

 certainly they are not. liut to l)ase nomenclature on phylogenetic 

 considerations would, in my opinion, be a rather dangerous prin- 

 ci})le; and in this particular case there are at least two reasons 

 which make it unadvisable to treat H. c. caffer and centralis as 

 distinct species: — first, though they, even where their areas overlaj) 

 each other and wdiere, consequently, they would seem to have 

 good o})portunity for intergradation , almost always preserve their 

 racial characters clear and well pronounced, intermediate examples 

 do occur, though a})parently very rarely (in a large number of 

 individuals, from many different places in East Africa, I have 

 found one only which is intermediate l)etween caffer and cen- 

 tralis); second, in Angola, where caffer, having come from east 

 (the Zambesi valley), and centralis, having come from northeast 

 (the Congo valley), live together, there also occurs a truly inter- 

 mediate « race », H. c. angolensis. These facts are strong evidence 

 that caffer and centralis are not sufficiently sharply differentiated 

 to be considered distinct species. — As being intermediate, the 

 Angolese « race » hardly deserves a technical name of its own , 

 but since the name angolensis is available, I do not see that it 

 can cause any harm to employ it, when only it is understood 

 Ihat l)y « H. c. angolensis » we mean but such specimens of 

 //. caffer from Angola as are intermediate between caffer and 

 centralis. 



