1902.J AND ANCIENT GEOGRAPHY. 327 



introduces among his regions of dispersal, as a seventh, an Indo- 

 African, which occupies this geographic position. He believes, 

 however, that it is not correct to explain certain similarities of the 

 faunas of India and Madagascar by a land-bridge, but prefers to 

 accept the existence of a chain of islands, which permitted, in later 

 Tertiary times, a migration of animals possessing the power of 

 flight (Birds, Bats) in this direction. On the other hand, he grants 

 a connection of Madagascar with Africa upward to the Miocene. 



Jacobi's assumption of a series of islands instead of a continental 

 connection from Madagascar to India seems to be well founded 

 only for this particular time, the younger Tertiary. But the simi- 

 larity of both faunas has apparently been underestimated by him, 

 even if he takes into consideration only Mammals and Birds, and 

 there are no doubt numerous relations between both parts among 

 other animals not possessing the power of flight. This fact has 

 been urged by Pilsbry (1894, p. xlv) for the Helices, and he says that 

 Madagascar is much more closely allied to Ceylon and Australia 

 than to South Africa. 1 The present cases offered by the genus 

 Astacoides and within the family of the Potamonidce are also very 

 important for this question, since the idea of a migration of these 

 forms over a chain of islands and across parts of the ocean is 

 entirely out of question. Thus it seems that we have to assume a 

 continental connection — if not during the later Tertiary — in earlier 

 times. 



The parts under discussion belong to the old Gondwana-land, 

 which, according to Suess, existed in Palaeozoic times, and was par- 

 tially destroyed in the same period through the disconnection of 

 Australia from it. Africa, however, remained intact, and formed 

 an ancient table-land, to which was added as a peninsula the 

 Lemurian bridge, which extended from Madagascar to India, and 

 traces of which are preserved up to the Eocene (Suess, 1885, 

 p. 538). This same peninsula is accepted by Neumayr for the 

 Jurassic period, and is represented in his map ; it is separated from 

 the main part of Africa by a great gulf extending southward, the 

 Ethiopian Mediterranean Sea, includes the present peninsula of 

 India, and is not connected with the Sino-Australian continent, the 

 Indian Gulf and the Strait of Bengal forming its northeastern 

 shores. According to Neumayr (1890, p. 390), this Indo-Mada- 

 gassian peninsula existed up to the end of the Cretaceous, and even 



1 In part, this may be due to old-Mesozoic, and even Palaeozoic geography. 



