404 ZOO-GEOGRAPHICAL NOTES. 



marcation in the whole of our territory, both for the vegetation 

 and the fauna, run nearly from south-east to north-west, and the 

 purely southern forms extend farther northwards in the west 

 than in the east. I learn from Lupton Bey that he has found 

 numbers of Ela'is (oil) palms in the west of the Bahr-el-Ghazal 

 basin, even in 6° N. lat., which first appear in our territory at 

 3° 40' N. lat. I have myself found in the Makraka territory, 

 in 4 45' N. lat., Calamus secundiflorus and Pandanus, the 

 former of which does not cross 2° 20' N. lat. farther to the 

 east, whilst the latter is wanting altogether. It is clear that 

 this striking variation of limits along the parallels of latitude is 

 determined by the differences of altitude and climate in the 

 region under consideration. As the boundary-line follows very 

 nearly the western slope of the ranges before mentioned, the 

 richer vegetation must be ascribed simply to more abundant 

 dews, inundation, and saturation of the soil, the existence of 

 such motive forces being proved by Casati's meteorological 

 records from Monbuttu, and more especially by Junker's carto- 

 graphical labours. 



The flora naturally harmonises with the fauna, and as the 

 western and southern varieties of plants penetrate much farther 

 northwards than has been supposed, corresponding animal 

 species will go hand in hand with them. Omitting altogether 

 older varieties, already cited by Heuglin, such as Agapornis, 

 which is not rare, but, on the contrary, very common, I will only 

 refer to some forms in my last collections from Monbuttu, — 

 Turacus giganteus, Yieill. ; Musophaga, sp. n. ; Corythaix persa, 

 L. ; Spermospiza hwmatina, Vieill. ; Pyrenestes ostrinus, L. ; 

 and from Makraka, still farther north, Nectarinia cyanocephala, 

 Sh. ; Pytelia Monteirii, Hartl. ; Hyphantomis ocularis, Sm. ; 

 Megalcema bilineata, Sund., and several kinds of Trichophorus. 

 As a result of all the facts now collected, the limit of 

 Wallace's " West African sub-region " must be pushed very 

 considerably to the east, and finds its natural boundary in the 

 mountains, which, starting from the Albert Lake, form on the 

 one hand the highlands of Amadi and Logo on the west and 

 north, and on the other send out spurs towards the north- 

 north-west, and subsequently to the north-west, which have 

 already been alluded to several times as the boundaries of the 



