Actinocyclids generally have an ovoid shape, but they can look extended when crawling. The dorsum is uniformly convex in profile. It can be smooth and covered with many small pustules, or even with large tubercles but does not have the spectacular network of spicules exhibited by the similar looking discodorids. The mantle is larger than the foot. The rhinophores are bulbous, lamellate, and retractile. The gills form a tight, circular cluster much like a goblet around the anal papilla at the posterior end of the dorsum and they can retract into a pocket below the mantle. Actinocyclids are usually very cryptic upon their sponge food source.