Srimad Bhagavatam Canto 09, Chapter 06, Text 03

SB 9.6.3

ete ksetra-prasuta vai
 punas tv angirasah smrtah
rathitaranam pravarah
 ksetropeta dvi-jatayah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Having been born from the womb of Rathitara’s wife, all these sons were known as the dynasty of Rathitara, but because they were born from the semen of Angira, they were also known as the dynasty of Angira. Among all the progeny of Rathitara, these sons were the most prominent because, owing to their birth, they were considered brahmanas.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Srila Visvanatha Cakravarti Thakura gives the meaning of dvi-jatayah as “mixed caste,” indicating a mixture of brahmana and ksatriya.
Srimad Bhagavatam Canto 09, Chapter 06, Text 02
Srimad Bhagavatam Canto 09, Chapter 06, Text 04