Megillah 23A

ורבא דמצלי אצלויי.

and Rava, who would bend their heads and not actually prostrate themselves on the ground.

ביום טוב חמשה, ביום הכפורים ששה כו׳. מתניתין מני? לא רבי ישמעאל ולא רבי עקיבא. דתניא: ביום טוב חמשה, וביום הכפורים ששה, ובשבת שבעה, אין פוחתין מהן ואין מוסיפין עליהן, דברי רבי ישמעאל. רבי עקיבא אומר: ביום טוב חמשה, וביום הכפורים שבעה, ובשבת ששה, אין פוחתין מהן אבל מוסיפין עליהן.

We learned in the Mishnah: On a Festival, 5 people read; on Yom Kippur, 6 people read; and on Shabbat, 7 people read. One may not decrease the number of readers, but one may add to them. The Talmud asks: Who is the tanna of the Mishnah? It is not R' Yishmael and not R' Akiva, as it is taught in a baraita: On a Festival, 5 people read from the Torah; and on Yom Kippur, 6 people read; and on Shabbat, 7 people read. One may not decrease or add to the required number of readers. This is the statement of R' Yishmael. R' Akiva disagrees and says: On a Festival, 5 people read from the Torah; and on Yom Kippur, 7 people read; and on Shabbat, 6 people read. One may not decrease these numbers, but one may add to them.

מני? אי רבי ישמעאל ⁠— קשיא תוספת! אי רבי עקיבא ⁠— קשיא ששה ושבעה!

Who is the tanna of the Mishnah? If you say it is R' Yishmael, it is difficult due to the ruling with regard to adding, as the Mishnah states that one may add additional readers but R' Yishmael holds that one may not do so. If you say it is R' Akiva, it is difficult due to the ruling concerning the days on which there are 13 readers.

אמר רבא: תנא דבי רבי ישמעאל היא. דתנא דבי רבי ישמעאל: ביום טוב חמשה, ביום הכפורים ששה, בשבת שבעה, אין פוחתין מהן אבל מוסיפין עליהן, דברי רבי ישמעאל.

Rava said: It is the tanna of the school of R' Yishmael, as it was taught in the school of R' Yishmael: On a Festival, 5 people read from the Torah; on Yom Kippur, 6 people read; on Shabbat, 7 people read. One may not decrease these numbers but one may add to them. This is the statement of R' Yishmael.