Xll 
IN TROD UCTION 
Indian Ocean. These two island districts are old 
mountain tops which have remained above water, their 
connexion with the African continent ceasine from the 
eocene period. The Comoro Isles and the Mascarenes, 
as well as the small islands lying far out in the ocean, 
are of volcanic nature and were probably raised above 
the surface of the water at a later date. The long 
duration of this isolation has not been without a far- 
reaching influence on the organic world. The indigenous 
genera are strikingly numerous, but the animals which 
immigrated in the miocene period and are so characteristic 
at present of Tropical Africa, are wanting. 
People have tried to ascribe a really ancient character 
to the human inhabitants, and to explain them as 
primitive forms standing between the races of Africa and 
Southern Asia. This was of course overshooting the 
mark, and the hypothesis did not correspond with the facts 
of the cases. Modern investigations have led to far 
more sober conclusions. The settlement of the East 
African Islands by man is of comparatively late date, having 
taken place, as regards a part of it, in later historic 
time, and it exhibits a motley chart of population, as 
the people belong to very different race elements and 
to no less than three different quarters of the Earth. 
No sufficient proof has yet been given of the existence 
of an autochthonous race. Lying beneath the magical 
sky of the Tropics these islands display a wealth of 
natural beauty which has long been renowned and which 
indeed cannot be surpassed in grandeur. 
Some of the islands have long attracted the attention 
of Europe as suitable districts for colonisation, and just 
