Diverticulum (mollusc anatomy)

As applied to mollusks, the Neo-Latin term diverticulum is an anatomical feature.

[4] Individual animals within the nudibranch clade Aeolidida have an array of long protruding structures called cerata on their dorsal surface.

Located within the cerata of these nudibranchs are hepatic diverticula, which are an outgrowth of the digestive gland or hepatopancreas of the animal.

Because of this, an aeolid nudibranch automatically takes on the colour of whatever substrate and food source it is living on and feeding on (for example, sea anemones or hydroids).

The diverticula also serve another important purpose because they pass along to the tips of the cerata any intact nematocysts that have been ingested from the food source.