Reference for Chullin 39:9

אמר רבה בר בר חנה

presumably the case where one twisted the organs around to the back of the neck!<span class="x" onmousemove="('comment',' In which case the slaughtering would be valid and the nipping invalid. This case, therefore, exemplifies the first clause of the rule stated, the second clause being added merely for the sake of completeness.');">²</span>

Jastrow