Complex sentence: The Wallace Line is a faunal boundary that run through the strait between Bali and Lombok, which, though a short distance, is a boundary between species of Asiatic origin in the east and a mixture of Australian and Asian species to the west.
Split into simpler sentences: The Wallace Line is a faunal boundary that runs through the strait between Bali and Lombok. It has been found to be a boundary between species of Asiatic origin in the east and a mixture of Australian and Asian species to the west.