Can you not inherited form non Arabs?

>A Hadith in Imam Malik's Muwatta Chapter: 27, Faraid 14 states Imam Malik's Muwatta >Yahya related to me from Malik from a reliable source of his who had heard Said ibn al-Musayyab say, ''Umar ibn al-Khattab refused to let anyone inherit from the non-arabs except for one who was born among the arabs." Malik said, "If a pregnant woman comes from the land of the enemy and gives birth in arab land so that he is her (an arab) child, he inherits from her if she dies, and she inherits from him if he dies, by the Book of Allah (al-Muwatta' ) Is this authenic if so can you explain it