Reference for Shabbat 214:5
ושאר שקצים כו': הא הורגן חייב מאן תנא א"ר ירמיה ר"א היא דתניא ר"א אומר ההורג כינה בשבת כהורג גמל בשבת מתקיף לה רב יוסף עד כאן לא פליגי רבנן עליה דרבי אליעזר אלא בכינה דאינה פרה ורבה אבל שאר שקצים ורמשים דפרין ורבין לא פליגי
For we learnt, R. Judah said: The halta'ah<span class="x" onmousemove="('comment',' A species of lizard. ');"><sup>8</sup></span> is like the weasel. But the Rabbis who disagree with R. Johanan b. Nuri in respect of defilement agree with him in respect of the Sabbath.<span class="x" onmousemove="('comment',' R. Judah holds that the question whether the skin of reptiles is like their flesh or not in the matter of defilement is not settled by deduction from the verse, 'and these are they which are unclean, etc.' (quoted supra a), but is dependent on touch. I.e., if the skin, is thick and perceptibly distinct from the flesh, it is not the same as the flesh; otherwise it is. By this criterion the halta'ah is like the weasel, since both have thick skins; though if the matter were decided by Scriptural exegesis these two would be dissimilar, as is shown in Hul. 142a. Hence he holds that in respect of the Sabbath, too, three of these eight have no skin, i.e., if one wounds them he is not guilty, for the skin is thin and not distinct from the flesh. But the Rabbis in Hul. count the halta'ah as one of the reptiles whose skin is the same as their flesh, in spite of its thickness. This shows that they settle the matter solely by reference to the verse, and therefore their view, which disagrees with R. Johanan b. Nuri's, applies only to defilement, since the verse is written in that connection, but not to the Sabbath. ');"><sup>9</sup></span>