68 
Annals op the Transvaal MusEtrM. 
The Chamaeleonidae have two other genera, Brookesia, confined to 
Madagascar, and Rhampholeon, of six species, which are distributed in 
East Africa from Mashonaland northwards to Somaliland. One species 
only extends from East Africa as far as Kamerun and Gabun in West 
Africa. 
The salient facts shown by the above are : South Africa, East Africa, 
and Madagascar have mutual relationships, and these areas contain the 
great majority of the species. The most widely-distributed African 
species extend north of the equator stretching from east to west, and are 
comprised in the same section as includes the single Indian species, the 
widely-distributed vulgaris of North Africa and the Mediterranean region, 
the two Arabian species — one of which is also recorded from the Nile — 
and the Socotran species. These facts seem to me not inconsistent with 
the hypothesis which so well explains the distribution and affinities of the 
other lizards, and we may, indeed, suppose the Chamaeleons had their 
home in the large island which comprised southern Africa and 
Madagascar. After the separation of Madagascar and the union of 
northern and southern Africa certain species which have special facilities 
for distribution spread northwards, penetrating into Europe, and one 
odd species passed, via North Africa or Arabia, even into India and Ceylon. 
The occurrence of Chamaeleons in all habitable parts of Africa and on 
numerous islands (Samo, Khio, Cyprus, Socotra, Comoro, Seychelles, 
Zanzibar, Mauritius, Bourbon, Canaries, and Fernando Po) undoubtedly 
points to the fact, which might not otherwise be suspected, that these 
creatures, have exceptionally good capacity for distribution, and in this 
respect they differ widely from the other endemic groups of southern 
Africa (Zonuridae, etc.), which, as I think, have remained content with 
the area which formed their ;original home. Chamaeleon remains have 
been reported from Eocene deposits in Wyoming, U.S.A., and from 
Oligocene strata at Quercy, France, which, no doubt, indicates that 
Chamaeleons are a comparatively old group, and had an extensive 
distribution in past ages. We need not, therefore, suppose that 
Chamaeleons actually originated in the Ethiopian island, but only that all 
the present day Chamaeleons had their ancestors in that area. 
According to Hollway (“ Science in South Africa ”), the northern 
boundary of South Africa, from a geographical point of view, is the great 
Congo-Zambesi divide, which stretches like a bridge from east to west 
across the continent from within a short distance of the Atlantic to the 
north end of LakeNyassa ; and I think it very probable that this boundary 
on the western half coincides with the northern boundary of the South 
African zoological area, but on the eastern side the highland area goes 
much further north, and so also does the South African fauna. 
Mr. W. L. Sclater has proposed ( Geog . Journal , 7, 282) to divide the 
Ethiopian region into four sub-regions, the Saharan, West African, Malagasy, 
and Cape sub-regions, and he then extended the Cape sub-region as far as 
the Congo watershed on the west and the Tana watershed on the east, which 
is entirely in agreement with my present conclusions ; but, later on, he 
found it “ increasingly difficult to draw any dividing line between the 
Saharan and Cape sub-regions ” (“ Science in South Africa ”, p. 150), and, 
limiting himself to the area south of the Zambesi and Cunene Rivers, he 
attempted to show that “ South Africa has not such a specialized fauna as 
was formerly attributed to it, and that it has comparatively little to 
distinguish it from the rest of the Ethiopian region ”. Now this 
generalization was based on the question of percentages of peculiar genera 
