במאי קמיפלגי תנא דבי רב ותנא דבי רבי ישמעאל בראשו ארוך קמיפלגי
The Gemara asks: With regard to what do the tanna of the study hall, who taught the first baraita above, and the tanna of the school of Rabbi Yishmael disagree? They disagree with regard to a grasshopper whose head is long. According to the tanna of the study hall it is prohibited, and according to the tanna of the school of Rabbi Yishmael it is permitted.
תנא דבי רב סבר אשר לו כרעים כלל ארבה סלעם חרגול חגב למינהו פרט כלל ופרט אין בכלל אלא מה שבפרט דמיניה אין דלאו דמיניה לא ומרבי דדמי ליה משני צדדין
The Gemara elaborates: The tanna of the study hall holds that the previous verse, permitting all species “which have jointed legs” (Leviticus 11:21), is a generalization. The species arbeh, solam, ḥargol, and ḥagav, and the phrase “after its kinds,” that appears after each, are a detail. As a rule, in any instance of a generalization and a detail, the generalization includes only that which is spelled out in the detail. Therefore, only grasshoppers of the same species as those detailed in the verse are kosher. Grasshoppers that are not of the same species as them are not kosher. And the phrase “after its kinds” amplifies the halakha to include grasshoppers that are similar to the named species in two aspects, i.e., that are very similar to them. Since all the named species have short heads, grasshoppers with long heads are forbidden.
תנא דבי ר' ישמעאל סבר אשר לו כרעים כלל ארבה סלעם חרגול חגב פרט למינהו חזר וכלל כלל ופרט וכלל אי אתה דן אלא כעין הפרט ומרבי כל דדמי ליה בחד צד
By contrast, the tanna of the school of Rabbi Yishmael holds that the phrase “which have jointed legs” is a generalization. The species arbeh, solam, ḥargol, and ḥagav are a detail. And by the phrase “after its kinds” after each species, it then generalized again. In any instance of a generalization, and a detail, and a generalization, you may deduce that the verse is referring only to items similar to the detail. And the verse therefore amplifies the halakha to include any grasshopper that is similar to the named species in even one aspect, i.e., that has the four signs listed in the mishna, even if its head is long.
והא לא דמי כללא קמא לכללא בתרא כללא קמא אשר לו כרעים אמר רחמנא דאית ליה אכול דלית ליה לא תיכול כללא בתרא עד דשוו בארבעה סימנין
The Gemara asks: But how can this be considered a generalization, a detail, and a generalization? The first generalization is not similar to the latter generalization. In the first generalization, the Merciful One states: “Which have jointed legs,” indicating that you may eat a grasshopper that has jointed legs, but you may not eat one that does not have jointed legs, irrespective of any other sign. However, the latter generalization: “After its kinds,” indicates that no grasshopper is kosher unless it shares all four signs with the named species.
תנא דבי ר' ישמעאל בכללי ופרטי כי האי גוונא דאין ודאמרי' נמי בעלמא דדאין תנא דבי ר' ישמעאל בכללי ופרטי כי האי גוונא מהכא:
The Gemara responds: The tanna of the school of Rabbi Yishmael deduces from generalizations and details like this case, even if the generalizations are not similar to one another. The Gemara notes: And that which we also say generally, that the tanna of the school of Rabbi Yishmael deduces from generalizations and details like this case, is derived from here.
אמר מר אי שמו חגב יכול אין בו כל הסימנין הללו ת"ל למינהו עד שיהו בו כל הסימנין הללו אין בו כל הסימנין הללו מהיכא תיתי ארבה וחרגול כתיב
The Gemara analyzes the baraita of the school of Rabbi Yishmael: The Master said: If its name must be ḥagav, one might have thought that any ḥagav is kosher, even if it does not have all these four signs. Therefore, the verse states: “After its kinds,” indicating that it is not kosher unless it has all these signs. The Gemara asks: From where would this be derived, that a grasshopper is kosher even if it does not have all these signs? How could one entertain this possibility? Arbeh and ḥargol are written beforehand, indicating that all kosher grasshoppers must share the signs they both possess.
אי לא כתיב סלעם כדקאמרת השתא דכתיב סלעם לרבויי ראשו ארוך אימא לירבי נמי כל דהו קמ"ל
The Gemara responds: If solam had not been written as well, it would be as you said. But now that it is written: “Solam,” to include long-headed grasshoppers even though none of the named species have long heads, I will say: Let us also include any grasshopper that is called ḥagav. Therefore, the phrase “after its kinds” teaches us that this is not so.
מאי שנא התם דאמרת סלעם זה רשון חרגול זה ניפול ומאי שנא הכא דאמרת סלעם זה ניפול חרגול זה רשון מר כי אתריה ומר כי אתריה:
The Gemara asks: What is different there, in the baraita of the study hall, that you say that the solam is the rashon, and the ḥargol is the nippul, and what is different here, in the baraita of the school of Rabbi Yishmael, that you say: The solam is the nippul, and the ḥargol is the rashon? The Gemara responds: This Sage refers to them in accordance with the custom of his locale and that Sage refers to them in accordance with the custom of his locale.
ובדגים כל שיש לו סנפיר וקשקשת: תנו רבנן אין לו עכשיו ועתיד לגדל לאחר זמן כגון הסולתנית והעפיאן ה"ז מותר יש לו עכשיו ועתיד להשירן בשעה שעולה מן המים כגון
§ The mishna states: And with regard to fish, any fish that has a fin and a scale is kosher. The Sages taught in a baraita: If a fish does not have scales now but will grow them after a period of time, such as the sultanit and afyan fish, it is permitted. Likewise, if it has scales now but will shed them when it is caught and rises from the water, such as