Diverticulum (mollusc anatomy)

Aeolidia papillosa showing cerata along its back the colour of recently eaten food

Diverticula are parts of a nudibranch's digestive gland located in its cerata. The diverticula allow the nudibranch to have a slender body and allows the nudibranch to be more buoyant. Because the skin is translucent, the contents of the diverticula can be seen, allowing the nudibranch to take on the colour of the anemone or other food that it is eating and thus blend in with its environment, providing the nudibranch with camouflage. The diverticula also passes ingested nematocysts to the tips of the cerata, where they can be used for defensive purposes.

References

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