This web site is devoted to the study of polyclad flatworms (Phylum: Platyhelminthes, Class: Turbellaria, Order: Polycladida), a group of large, free-living marine flatworms which are mainly found in tropical coral reefs. Although not related to molluscs (Phylum: Mollusca) they are often mistaken for sea slugs (Order: Nudibranchia) because of their brilliant colour patterns.

Collecting images and data about their occurrence, taxonomy and biology these pages may contribute to our knowledge about biology and distribution of these colourful marine invertebrates. Visitors interested in polyclad biology will find an introduction to polyclads below. Since some species shown here could not be exactly identified or have not yet been described, the visitors comments are highly appreciated!

Please note, that most images on these pages have been contributed by enthusiastic UW-photographers bona fide and, therefore, may not be used without written consent of the corresponding author/photographer except for the visitor's private and non-commercial use!

Hopefully, these pages will become a way for underwater photographers and marine biologists to share photos of polyclads which are possibly new!