Diverticula (mollusc)
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Diverticula is an anatomical term for a set of organs which are visible from the outside on a group of colorful sea slugs known as nudibranchs, which are marine opisthobranch gastropod mollusks.
These diverticula are located in the cerata of a nudibranch and they contain parts of the digestive gland of the animal. The diverticula allow the nudibranch to have a slender body, and allow the nudibranch to be more buoyant.
But more essentially, because the nudibranch's skin is translucent, the contents of the diverticula are easily visible; this means that the nudibranch automatically takes on the exact colour of whatever substrate and food source it is living on and feeding on (for example, sea anemones, hydroids, etc). Because of this, visually the animal blends perfectly with its environment, providing excellent camouflage.
The diverticula are also important because they pass any intact nematocysts (which have been ingested from the food source) along to the tips of the cerata, where these stinging cells are then available to defend the nudibranch itself against predation.
