Reference for Chullin 252:50

טימא בחולדה וטימא בעכבר מה חולדה מין הגדל על הארץ אף עכבר מין הגדל על הארץ

Or you might argue in this way: [Scripture] declared the weasel unclean and the mouse unclean, therefore as the weasel refers to every creature which bears the name weasel, so the mouse refers to every creature which bears the name mouse, and so it will include the sea-mouse since it bears the name mouse! The text therefore teaches: Upon the earth.<span class="x" onmousemove="('comment',' Ibid. This serves to exclude those that live in the sea.');">²³</span>

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