Bibliographia Nudibranchia, Gary McDonald - A searchable comprehensive bibliography of the literature about nudibranchs, exluding textbooks and local field guides.

Sharif's Malaysian Slugsite - Contains photographs of Malaysian nudibranchs and links to other nudibranch sites.

Opisthobranchia Around Hachijo Island - Photographs of nudibranchs from the Izu-Islands group of Japan.

Nudibranchs of Madeira, Canary Islands and the Azores - A collection of photographs by Dr. Peter Wirtz.

Nudibranchs of the British Isles - A profusely illustrated on-line guide to the identification of Britain's seaslugs.

Pacific Coast Nudibranchs - General background information about nudibranchs and a key to those inhabiting the Pacific coast of North America. Work of a student at UCSC and Gary MacDonald.

Jeff's Nudibranch Page - Devoted primarily to the nudibranchs of the Philippines, but also contains information and photographs about crinoids (Echinodermata) and reef organisms in general.

The Slug Site - Devoted to the study of opisthobranch molluscs.

The Okinawa Slug Site - A site featuring Okinawan Opisthobranch Molluscs, nudibranchs and other related sea slugs such as bubble-shells, sea hares and side-gilled slugs.

Sea Slug Forum - You can ask questions and post information on nudibranchs and other related sea slugs such as bubble-shells, sea hares and side-gilled slugs.

Opisthobranchs of Ross Island & McMurdo Sound, Antarctica - Electronic field guide of Antarctic opisthobranchs. Part of overall marine field guide to Antarctica. Web site by Peter Brueggeman, SIO librarian. Photos by Norbert Wu, P. Brueggeman, and Kathleen Conlan.

Photos of Indo-Pacific and Red Sea Nudibranchs - A collection of photographs in which information on the camera, film used, and some species specific data are provided with each photo. [Pop-ups].

Em nau! Nudibranchs - A rundown of some of the nudibranchs found in Papua New Guinea. Part of a larger site dedicated to this corner of the world.

Scottish Nudibranchs - Deals almost exclusively with this part of the world.

Nudibranchs and Marine Flatworm of the World - Photos of nudibranchs from the Mediterranean, Indian Ocean, and the Red Sea. Unfortunately (from a certain perspective), there is more information about flatworms on this site than about nudibranchs.

Garry's Nudibranch Page - Homepage of nudibranchs found off the shores of Southern California. Photos contain species info, and the camera and film used.

Fabio's Nudibranch Gallery - A small gallery of nudibranch pictures that is part of Fabio's Sealife Picture Gallery.

Nudibranchs of the Poor Knight Islands - Images of some New Zealand nudibranchs.

Opisthobranchs of Kii Penninsula - The page is in Japanese.

Opisthobranchs of the coast of Granada - This site is in Spanish.

Nudibranch X-Files Index Page - A list of nudibranch photographs. The photographs include information about the location of the photo, the camera used, and the film used. The page is part of cybereef.com.

Australian Nudibranchs - Description, classification and photographs of nudibranchs, as well as the Australasian Nudibranch News, an online newsletter dedicated to nudibranchs of the Australia/Asia region. Part of a larger site devoted to Australian scuba diving.

Sulawesi Sea Slugs - Images and information of species seen near North Sulawesi, Indonesia in June 2001.

Sea Slugs from Japan - A well organized site. Available in English and Japanese.

Nudibranchs of Costa Rica: The Slugophile - Photographs, an interactive sightings form for divers from around the world, some general information, and a touch of anatomy. Concentrated mostly on opisthobranchs of Costa Rica.

Singapore Nudibranchs - Data available on sites and dates of collection of nudibranchs.

Nudibranchs of Norway - Knowledge of Norwegian suggested for this site.