Completely revised and updated by 68 experts in the field, the new edition of this essential text features expanded coverage, mentioning most valid modern genera. The book is lavishly illustrated with over 4,200 figures, illustrations, and drawings (over half of them new), and is organized by monophyletic assemblages using latest higher-group taxonomic consenses. Other features include easy-to-use taxonomic keys to each chapter, a glossary, and organism and subject indices.