Mbh 12.297.2

"'"Parasara said, 'It is as thou sayst, O king! The offspring procreated are none else than the procreator himself. In consequence, however, of falling away from penance, this distribution into classes of different colours has taken place. When the soil becomes good and the seed also is good, the offspring produced become meritorious. If, however, the soil and seed become otherwise or inferior, the offspring that will be born will be inferior. They that are conversant with the scriptures know that when the Lord of all creatures set himself to create the worlds, some creatures sprang from his mouth, some from his arms, some from his thighs, and some from his feet. They that thus sprang from his mouth, O child, came to be called Brahmanas. They that sprang from his arms were named Kshatriyas. They, O king, that sprang from his thighs were the wealthy class called the Vaisyas. And, lastly, they that were born of his feet were the serving class, viz., the Sudras. Only these four orders of men, O monarch, were thus created. They that belong to classes over and other than these are said to have sprung from an intermixture of these. The Kshatriyas called Atirathas, Amvashthas, Ugras, Vaidehas, Swapakas, Pukkasas, Tenas, Nishadas, Sutas, Magadhas, Ayogas, Karanas, Vratyas, and Chandalas, O monarch, have all sprung from the four original orders by intermixture with one another.'