| 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. |
| Bibliographia Nudibranchia, Gary McDonald: A searchable comprehensive bibliography of the literature about nudibranchs, exluding textbooks and local field guides. |
| 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. |
| Fabio's Nudibranch Gallery: A small gallery of nudibranch pictures that is part of Fabio's Sealife Picture Gallery. |
| 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. |
| Mediterranean Slug Site: A plethora of photos and information about Opisthobranchs from the Mediterranean Sea. Also includes nudibranchs from parts of the world other than the Mediterranean. |
| Nudibranch Roundup: Photographs and introduction by Phillip Slosberg. |
| 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. |
| 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. |
| Nudibranchs of Norway: Knowledge of Norwegian suggested for this site. |
| Nudibranchs of the Poor Knight Islands: Images of some New Zealand nudibranchs. |
| Opisthobranchia Around Hachijo Island: Photographs of nudibranchs from the Izu-Islands group of Japan. |
| Opisthobranchs of Kii Penninsula: The page is in Japanese. |
| 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]. |
| Scottish Nudibranchs: Deals almost exclusively with this part of the world. |
| 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. |
| Sharif's Malaysian Slugsite: Contains photographs of Malaysian nudibranchs and links to other nudibranch sites. |
| Singapore Nudibranchs: Data available on sites and dates of collection of nudibranchs. |
| Sulawesi Sea Slugs: Images and information of species seen near North Sulawesi, Indonesia in June 2001. |
| 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. |
| The Slug Site: Devoted to the study of opisthobranch molluscs. |
Classical
