Answer:
The mouth covered by chitin and intracellular granules of chitin (i.e. spindles) in nudibranchs
Explanation:
Nudibranchs are marine gastropod molluscs (Opisthobranchia, Mollusca). These organisms are carnivorous, so they feed on sponges, coral, anemones, hydroids, fish eggs, etc. On the other hand, cnidarians have specialized cells called cnidoblasts or cnidocytes that contain nematocysts made up of toxins that serve as a defense mechanism. Nematocysts are found in many species of Cnidarians such as, for example, in the tentacles of sea anemones. Interestingly, nudibranchs have developed some adaptations for feeding on these species. In the first place, nudibranchs have the mouth covered by a substance named chitin that allows them to chomp and swallow anemone tentacles. Second, they (nudibranchs) also have intracellular granules of chitin (i.e. spindles) in the digestive system that function as biological sandbags which maintain nematocyst toxins away from sensitive body parts.
