In spite of its proximity to Africa (the distance between Cap Saint- Andre and the African coast is only 300 km. ) Madagascar cannot be considered as adependent part of that continent. The Great Island has been separated from Mrica from at least the middle of the Secondary, and has evolved separately: its flora and fauna have acquired a very pronounced individuality, in spite ofsome affinities with Africa (although they also have affinities with India and the Indian archipelago). No naturallaboratory could lend itselfbetter ifnot to all, at least to the majority, of the absorbing problems...