Evolutionary Biology, of which this is the twenty-second volume, continues to offer its readers a wide range of original articles, reviews, and commentaries on evolution, in the broadest sense of that term. The topics of the reviews range from anthropology, molecular evolution, and paleobiology to principles of systematics. In recent volumes, a broad spectrum of articles have appeared on such subjects as asymmetric sexual isolation, biochemical systematics in plants, species selection, DNA hybridization and phylogenetics, modes of evolution in Pleistocene rodents, and development and evolution of the vertebrate limb. We have also attempted to provide a forum for con flicting ideas. Articles such as these, often too long for standard journals, are the material for Evolutionary Biology. The editors continue to solicit manuscripts on an international scale in an effort to see that everyone ofthe many facets of biological evolution is covered. Manuscripts should be sent to anyone of the following: Max K. Hecht, Department of Biology, Queens College of the City University of New York, Flushing, New York 11367; Bruce Wallace, Department of Biology, Virginia Polytechnic Institute and State University, Blacks burg, Virginia 24061; GhilleanT. Prance, New York Botanical Garden, Bronx, New York 10458. The Editors vii Contents 1. Phylogeny of Early Vertebrate Skeletal Induction and Ossification Patterns. 1 John G. Maisey Introduction: The Fossil Record. 1.

Inhaltsangabe1. Phylogeny of Early Vertebrate Skeletal Induction and Ossification Patterns.- Introduction: The Fossil Record.- The Vertebrate Skeleton.- The Products of Skeletogenesis.- Sites of Skeletogenesis.- Skeletal Enlargement.- Cartilage.- Bone.- Dentines and Enamel.- Skeletalization versus Calcification.- The Problem of Ontogenetic Similarity.- The Phylogenetic Basis of Investigation.- Findings.- Primitive Vertebrate Hard Tissues.- Early Vertebrate Induction Mechanisms.- Gnathostomes: Variations on a Theme.- Discussion.- Conclusions.- Appendix: Characters Related to Vertebrate Skeletogenesis.- References.- 2. A Review of the Origin of Snakes.- The Paleontological Evidence and Early Theories of Snake Origins.- The Affinities of Snakes.- The Scolecophidian Basicranium.- The Trabeculae Cranii.- The Nasal Capsule.- The Alary Process of the Prootic.- The Metotic Fissure.- The Stapedial Artery.- Adventitious Cartilage.- Epiphyses.- Distally Forked Ribs.- Limb Reduction.- The Constrictor Internus Dorsalis Group.- The Jaw Adductor Musculature.- The Hyobranchium and Throat Musculature.- The Trunk Musculature.- The Brain.- The Retina.- The Inner Ear.- The Nose and Associated Structures.- The Oral Glands.- The Thymus.- The Intestine.- The Pancreas.- The Bile Salts.- The Adrenal.- Cardiac Anatomy.- The Hemipenis.- The Chromosomes.- The Anguimorph Hypothesis.- The "Burrowing Lizards" Hypothesis.- Discussion and Conclusions.- The Classification of Snakes: Basic Divisions.- A Historical Review of Snake Classification.- A Cladogram of Snakes: Basic Divisions.- The Monophyly of the Scolecophidia.- The Monophyly of the Henophidia.- The Monophyly of the Anilioidea.- The Monophyly of the Booidea.- The Monophyly of the Caenophidia.- The Classification of Dinilysia patagonica Woodward.- Summary and Conclusions.- The Ecology of Snake Origins.- New Fossils and New Ideas.- The Hypothesis of a Burrowing Origin of Snakes.- The Ear of Snakes.- The Nose of Snakes.- The Tongue of Snakes.- The Loss of Limbs.- Cranial Kinesis in Burrowing Lizards and the Jaw Mechanics of Snakes.- The Origin of Snakes and the Rise of Mammals.- Miniaturization: A Unifying Concept.- References.- 3. Horses, the Fossil Record, and Evolution: A Current Perspective.- Fossil Horses and Evolutionary Thought.- Origin and Diversification of the Perissodactyla.- Synoptic History of Horses: The First 25 Million Years.- The Miocene: Acme of Horse Evolution.- The Last Eight Million Years of Horse Evolution.- Selected Evolutionary Principles.- Trends.- Modes.- Rates.- Mosaics.- Summary and Conclusions.- References.- 4. Historical Biogeography of the Drosophila melanogaster Species Subgroup.- Biogeographic and Ecological Evidence.- The Biogeography of the Species.- The Breeding Sites.- Unequivocal versus Equivocal Phylogenetic Relationships.- Paleobiogeographic Inferences.- Dispersal Tracks, Vicariance Biogeography, and the Refuge Theory.- Fragmentation of the African Tropical Forest and the Refuge Theory.- An Ancestor Originating from Asia.- Splitting of the Primeval Trunk into Two Branches.- The Three-Root Stage.- The Drosophila erecta-Drosophila orena Divergence May Have Occurred in the West Cameroon Mountains.- The Refuge Theory Possibly Valid for the Drosophila teissieri-Drosophila yakuba Differentiation.- The 2- to 3-MYA Rift Aridification: A Plausible "Vicariant" Event Resulting in Drosophila melanogaster and the Ancestor of the Three Drosophila simulans-like Species.- Oversea Dispersal, Founder Effect, and Speciation within the Drosophila simulans Lineage without Novel Chromosomal Rearrangements.- Three Drosophila simulans "Races".- Equatorial Africa Is Presumably the Historic Zone of Secondary Contact between Drosophila melanogaster and Drosophila simulans.- The Northward Migration of Drosophila melanogaster: The Trans-Saharan Route.- The Northward Migration of Drosophila simulans: The Nile Route?.- Concluding Remarks and Summary.- References.- 5. Aposematism and Batesian Mimicry: Measur