Reference for Chullin 149:45

ואיכא דאמרי איתיביה רבי שמעון בן לקיש לרבי יוחנן

R'Ammi said: If a person slaughtered a trefah animal and found in it a nine months' living foetus, according to him who forbids [the other<span class="x" onmousemove="('comment',' The nine months' living foetus found in the womb of a slaughtered animal; v. supra, the Mishnah 740.');">²⁷</span>

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