tegument!
monogenea are ectoparasitic while trematoda are endoparasitic
tegument
Flukes have a protective covering called a tegument that helps them evade the digestive enzymes of their hosts. The tegument acts as a barrier, preventing the enzymes from reaching the fluke's body. Additionally, some flukes have evolved mechanisms to neutralize or resist the effects of digestive enzymes.
protective covering (a lead apron)
Armor.
cornea
The protective covering on the package was damaged. She is as protective as a mother hen.
The skin (or hide) and fur are the protective covering of a raccoon.
it's shell..
Enamel.
Yes!
Chaps!