Siphonophores and velellids

To all except marine biologists, the Portuguese man-o’war Physalia is often regarded as the only British siphonophore. Most of the fragile, beautiful and anatomically complex siphonophores are members of the plankton, seldom seen as complete organisms but nearly always as transparent fragments in plankton samples.

This Synopsis contains full accounts of the 55 species of siphonophore which have been found in British and Irish waters, along with the only British velellid, the ‘Jack sail-by-the-wind’ (Velella velella).