TT #266 · Parshas Shemini · Aliyah 7 · Passuk 47
Chabad.org — Vayikra Chapter 11 with Rashi
English: To distinguish between the impure and the pure, and between the animal that may be eaten and the animal that may not be eaten.
Chullin 42b.
E-Daf.com — Chullin 42b (Tsurras Hadaf)
English: “And between the animal that may be eaten and the animal that may not be eaten”: these are the eighteen categories of tereifah that were told to Moshe at Sinai.
Textual derivation — the Torah’s distinction between the two categories is used to identify the eighteen categories of tereifah.
The closing distinction includes the traditional tereifah categories.