The Brahmans, the Incas, and the rulers?

1) Does "the Brahmans, the Incas, and the rulers" refer back to "the ruling caste or race"?

2)"has, therefore, evidently immigrated"? Immigrated to where?

Background info:

The highest civilization and culture, apart from the ancient Hindus and Egyptians, are found exclusively among the white races; and even with many dark peoples, the ruling caste or race is fairer in colour than the rest and has, therefore, evidently immigrated, for example, the Brahmans, the Incas, and the rulers of the South Sea Islands. All this is due to the fact that necessity is the mother of invention because those tribes that emigrated early to the north, and there gradually became white, had to develop all their intellectual powers and invent and perfect all the arts in their struggle with need, want and misery, which in their many forms were brought about by the climate. This they had to do in order to make up for the parsimony of nature and out of it all came their high civilization.^{http://en.wikipedia.org/wiki/Arthur_Schopenhauer#cite_note-43}