This important work updates siphonophore taxonomy for the first time in 40 years, applying and extending the new holistic terminology recently introduced by other authors and providing full synonymies for many common species. Divided into 10 sections, it includes general sections on systematics, life cycles, and ecology; detailed descriptions and diagnoses for 37 species collected from Canadian Pacific waters; relevant genus and family diagnoses; and three keys. With more than 60 figures (including many camera lucida line drawings), this book should prove invaluable to taxonomists, deep ocean researchers, and evolutionary geneticists working on cnidarian phylogenetic relationships.