
Proctonotidae is a family of sea slugs, nudibranchs, marine gastropod molluscs, in the clade Euthyneura.

Antiopella barbarensis, common name Santa Barbara janolus, is a colourful sea slug, a cladobranch nudibranch, a marine gastropod mollusc in the family Janolidae.
Antiopella cristata, sometimes known by the common name crested aeolis, is a species of nudibranch, a marine gastropod mollusc in the family Janolidae.

The gasflame nudibranch is a very colourful species of nudibranch, or sea slug. It is a marine gastropod mollusc in the family Proctonotidae. Bonisa nakaza is the only species in the genus Bonisa.

Janolus is a genus of small to large sea slugs, or more accurately nudibranchs, marine gastropod mollusks, in the family Proctonotidae. The name Janolus is derived from the two-headed god Janus, in ancient Roman mythology.

Janolus capensis, the Cape silvertip nudibranch, is a beautiful species of nudibranch, or sea slug. It is a marine gastropod mollusc in the family Proctonotidae.

Janolus fuscus is a species of sea slug, or more accurately a nudibranch, a marine gastropod mollusk in the family Proctonotidae.

Janolus longidentatus, the medallion silvertip nudibranch, is a spectacular-looking species of nudibranch, or sea slug. It is a marine gastropod mollusc in the family Proctonotidae.

Janolus savinkini, common name purple-tipped janolus, is a colorful sea slug, an arminina nudibranch, a marine gastropod mollusc in the family Proctonotidae. The body and caruncle of this species are yellow with a hue of light orange. The papillae and cerata are also this colour except for the tips, which are blue/purple, hence the common name. It is found in East Asian waters and is believed to be extremely rare in Okinawa.

Janolus toyamensis, common name purple-tipped janolus, is a colorful sea slug, an arminina nudibranch, a marine gastropod mollusc in the family Proctonotidae.