Reference for Menachot 107:12

אימא וכן בטומאת פיגול וכן בטומאת נותר

and the flesh<span class="x" onmousemove="('comment',' An egg's bulk.');">¹⁵</span> of an old beast that had shrivelled,<span class="x" onmousemove="('comment',' To less than an egg's bulk.');">¹⁶</span>

Jastrow