Available free from Scientific American's Website, this article takes a thorough and fascinating look at the marine reptiles known as Ichthyosaurs that lived during the Mesozoic Era. The text covers recent discoveries about the evolution of Ichthyosaurs from land dwelling reptiles, including limb adaptations. Highlights of the article are special sections about ichthyosaur eyes and diet, and color illustrations and diagrams. The text contains hyperlinks to related pages (Britannica.com, Tree of Life, American Cetacean Society, etc.). "Rulers of the Jurassic Seas" is a good read for students of paleontology or marine science.