(Mishnah): If [a Nazir Shimshon] becomes Tamei, he does not bring Korban Tum'ah.

Inference: It says only that he does not bring Korban Tum'ah (i.e. he has no Isur of becoming Tamei), but he is lashed [for other Isurim of Nezirus, i.e. wine and shaving].

Our Mishnah is like R. Yehudah, for a Beraisa teaches in the name of R. Yehudah, a Nazir Shimshon may become Tamei, for Shimshon became Tamei through Mesim.

R. Shimon says, if he said 'like Shimshon', it has no effect, for Nezirus did not take effect on him through his mouth.

What is the source? "K'Fi Nidro" - one whose Nezirus took effect through his mouth. This excludes Nezirus Shimshon, which did not take effect on him through his mouth, rather, through prophecy.

What is the source [that Shimshon's Nezirus took effect on him through prophecy]? "Ki Nazir Elokim Yihyeh ha'Na'ar Min ha'Beten."