Mishneh Torah — Transmission of the Oral Law מסירת תורה שבעל פה, Chapter 8

אַנְטִיגְנוֹס אִישׁ שׂוֹכוֹ וּבֵית דִּינוֹ קִבְּלוּ מִשִּׁמְעוֹן הַצַּדִּיק וּבֵית דִּינוֹ, וְיוֹסֵף בֶּן יוֹעֶזֶר אִישׁ צְרֵדָה וְיוֹסֵף בֶּן יוֹחָנָן אִישׁ יְרוּשָׁלַיִם וּבֵית דִּינָם קִבְּלוּ מֵאַנְטִיגְנוֹס וּבֵית דִּינוֹ, וִיהוֹשׁוּעַ בֶּן פְּרַחְיָה וְנִתַּאי הָאַרְבֵּלִי וּבֵית דִּינָם קִבְּלוּ מִיּוֹסֵף וְיוֹסֵף וּבֵית דִּינָם, וִיהוּדָה בֶּן טָבַאי וְשִׁמְעוֹן בֶּן שָׁטָח וּבֵית דִּינָם קִבְּלוּ מִיְּהוֹשׁוּעַ וְנִתַּאי וּבֵית דִּינָם. שְׁמַעְיָה וְאַבְטַלְיוֹן גֵּרֵי הַצֶּדֶק וּבֵית דִּינָם קִבְּלוּ מִיְּהוּדָה וְשִׁמְעוֹן וּבֵית דִּינָם. וְהִלֵּל וְשַׁמַּאי וּבֵית דִּינָם קִבְּלוּ מִשְּׁמַעְיָה וְאַבְטַלְיוֹן וּבֵית דִּינָם. וְרַבַּן יוֹחָנָן בֶּן זַכַּאי וְרַבַּן שִׁמְעוֹן בְּנוֹ שֶׁלְּהִלֵּל קִבְּלוּ מֵהִלֵּל וּבֵית דִּינוֹ.

Antignos of Socho and his court received the tradition from Shimon the Just and his court.Yosse ben Yo'ezer of Tzreidah and Yosef ben Yochanan of Jerusalem (pairs) mentioned in the first chapter of Avot. The first of the sages mentioned was the nasi (head of the academy), and the second the av beit din (head of the court). and their court received the tradition from Antignos and his court. Yehoshua ben Perachiah and Nittai of Arbel and their court received the tradition from Yosse ben Yo'ezer and Yosef ben Yochanan and their court. Yehudah ben Tabbai and Shimon ben Shatach and their court received the tradition from Yehoshua ben Perachiah and Nittai of Arbel and their court. Shemayah and Avtalion, who were righteous converts, 1:3 and Gittin ,57b. It is difficult to understand why the Rambam mentions Shemayah and Avtalion's ancestry. On the contrary, the fact that they were converts raises serious questions as to why they were allowed to serve as nasi and av beit din. (See Hilchot Melachim 1:4 and the commentary in the Moznaim edition of that Halachah.) and their court received the tradition from Yehudah and Shimon and their court.Hillel and Shammai and their court received the tradition from Shemayah and Avtalion and their court. Rabban Yochanan ben Zakkai and Rabbi Shimon, the son of Hillel the elder, received the tradition from Hillel [and Shammai] and his [their] court[s].