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 Hlais (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 cartographical 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, Vieill.; Musophaga, sp. n.; Corythaix persa, L.; Spermospiza hematina, Vieill.; Pyrenestes ostrinus, L. ; and from Makraka, still farther north, WVectarinia cyanocephala, Sh.; Pytelia Montewu, Hartl.; Hyphantornis ocularis, Sm. ; Megalema 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 Loégo on the west and north, and on the other send out spurs towards the northnorth-west, and subsequently to the north-west, which have already been alluded to several times as the boundaries of the