A COMPARATIVE REVIEW OF THE AMPHIBIAN FAUNAS OF 
SOUTH AFRICA AND MADAGASCAR, WITH SOME SUGGES- 
TIONS REGARDING THEIR FORMER LINES OF DISPERSAL. 
By John Hewitt, B.A. (Cantab.). 
Since the publication of the British Museum Catalogue of Batrachia 
Salientia several important additions have been made to our knowledge 
of the amphibian fauna of South Africa : these are incorporated in my 
paper on the South African Batrachia in the Becords of the Albany Museum. 
Vol. 2, No. 3 ; and in a recent paper, Nouv. Archiv. du Museum d’Hist. Nat., 
Paris, 1909, Dr. F. Mocquard gives a complete list of the Batrachia of 
Madagascar. These lists seemed to offer a favourable opportunity for 
examining the known facts of distribution in terms of certain modern 
theories on the past configuration of the earth’s surface. Those theories 
may be briefly stated as follows : From geological considerations it is 
believed that in Permian times a large Indo-oceanic continent connected 
together Australia, India, Madagascar, the Seychelles and southern Africa, 
and these connections persisted as late as the Upper Cretaceous period, 
but were broken up into islands at an early tertiary date : the derite 
connection between Australia and South Africa disappeared first, but 
Dr. Schonland believes , on botanical evidence, that it was still in existence 
during Lower Cretaceous times (see Trans. S. Afric. Phil. Soc., 18. 3. , p. 321) : 
the land connection between Madagascar and India persisted until the 
Eocene period, or perhaps considerably later as an archipelago, and there 
is abundant zoological evidence that the union between Madagascar and 
southern Africa is also of recent date, and indeed as a series of swamps 
may even have continued into the early Pliocene. On the other hand, 
from similar considerations it is hardly less certain that an extensive land 
connection has existed between the neotropical region and West Africa 
during the later secondary and early tertiary periods. Contemporaneous 
with these far-reaching land bridges across the Atlantic and Indian Oceans 
of the later secondary period, a great sea, perhaps dotted with islands, 
stretched north of the Equator from Panama by way of Africa as far as 
southern Asia, and thus the southern land-mass which included southern 
Africa and Madagascar was quite cut off from the palaearctic region. At 
that time the fauna of this large land-mass would have much in common 
throughout large areas, without being absolutely homogeneous, but after the 
separation of Madagascar and the formation of the African continent in its 
present shape, a new fauna coming from the palaearctic region arrived in 
South Africa, but was unable to reach Madagascar by this time an island. 
The present-day fauna of Madagascar should therefore be of particular 
interest, as it preserves, with but little admixture of foreign forms, the 
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