Bava Basra 2a
How many Mesechtos are there in Seder Nezikin?
10 - 8 - 1 ?
R. Yosef said "כולה נזיקין חדא מסכת". R. Huna argues and considers them as separate Mesechtos. (Bava Kama 102a)
There are important Halachic differences if we count them as one or separate Mesechtos.
(אין סדר למשנה only applicable in same (1) Mesechta)
*Although the general rule is, we Pasken like R. Huna against R. Yosef, in this case, the Halacha (Rambam) is like R. Yosef being Rebbi named the three Mesechtos " Bava
Kama,Metzia & Basra". (gate 1,2,3 - one Mesechta with 3 gates)
There is also a Machlokes Rishonim if Reb Yosef referred to, only the first three Mesechtos
as Kulo Nezikin (Bava Kama Metzia Basra)
or all 10 Mesechtos are considered one.
1) 10 R. Huna
2) 8 R. Yosef (Rambam Ritva)
3) 1 R. Yosef (Ri Migash**)
* Hakdama Tosfos Yom Tov
** The first Maharsha in Bava Basra seems to agree with the Ri Migash