The fruitfly Drosophila melanogaster is an ideal model system to study processes of the central nervous system This book provides an overview of some major facets of recent research on Drosophila brain development.

" . . . but our knowledge is so weak that no philosoph er will ever be able to completely explore the nature of even a fly . . . " * Thornas Aquinas "In Syrnbolurn Apostolorum" 079 RSV p/96 This is a monograph on embryogenesis of the fruit fly Drosophi la melanogaster conceived as a reference book on morphology of embryonie development. A monograph of this extent and con tent is not yet available in the literature of Drosophila embryolo gy, and we believe that there is areal need for it. Thanks to the progress achieved during the last ten years in the fields of devel opmental and molecular genetics, work on Drosophila develop ment has considerably expanded creating an even greater need for the information that we present here. Our own interest for wildtype embryonie development arose several years ago, when we began to study the development of mutants. While those studies were going on we repeatedly had occasion to state in sufficiencies in the existing literature about the embryology of the wildtype, so that we undertook investigating many of these problems by ourselves. Convinced that several of our colleagues will have encountered similar difficulties we decided to publish the present monograph. Although not expressely recorded, Thomas Aquinas probably referred to the domestic fly and not to the fruit fly. Irrespective of which fly he meant, however, we know that Thomas was right in any case.

1 Kevin Moses It is now 25 years since the study of the development of the compound eye in Drosophila really began with a classic paper (Ready et al. 1976). In 1864, August Weismann published a monograph on the development of Diptera and included some beautiful drawings of the developing imaginal discs (Weismann 1864). One of these is the first description of the third instar eye disc in which Weismann drew a vertical line separating a posterior domain that included a regular pattern of clustered cells from an anterior domain without such a pattern. Weismann suggested that these clusters were the precursors of the adult ommatidia and that the line marks the anterior edge of the eye. In his first suggestion he was absolutely correct - in his second he was wrong. The vertical line shown was not the anterior edge of the eye, but the anterior edge of a moving wave of patterning and cell type specification that 112 years later (1976) Ready, Hansen and Benzer would name the "morphogenetic furrow". While it is too late to hear from August Weismann, it is a particular pleasure to be able to include a chapter in this Volume from the first author of that 1976 paper: Don Ready! These past 25 years have seen an astonishing explosion in the study of the fly eye (see Fig.

Comprehensive and authoritative, The Wiley Handbook of Evolutionary Neuroscience unifies the diverse strands of an interdisciplinary field exploring the evolution of brains and cognition. A comprehensive reference that unifies the diverse interests and approaches associated with the neuroscientific study of brain evolution and the emergence of cognition Tackles some of the biggest questions in neuroscience including what brains are for, what factors constrain their biological development, and how they evolve and interact Provides a broad and balanced view of the subject, reviewing both vertebrate and invertebrate anatomy and emphasizing their shared origins and mechanisms Features contributions from highly respected scholars in their fields

Most of the cranial sense organs of vertebrates arise from embryonic structures known as cranial placodes. Such placodes also give rise to sensory neurons that transmit information to the brain as well as to many neurosecretory cells. This book focuses on the development of sensory and neurosecretory cell types from cranial placodes by introducing the vertebrate head with its sense organs and neurosecretory organs and providing an overview of the various cranial placodes and their derivatives, including evidence of common embryonic primordia. Schlosser discusses how these primordia are established in the early embryo and how individual placodes develop. The latter chapters explain how various placodally derived sensory and neurosecretory cell types differentiate into discrete structures.

Developmental biology is one of the most exciting and fast-growing fields today. In part, this is so because the subject matter deals with the innately fascinating biological events—changes in form, structure, and function of the org- ism. The other reason for much of the excitement in developmental biology is that the field has truly become the unifying melting pot of biology, and provides a framework that integrates anatomy, physiology, genetics, biochemistry, and cellular and mole- lar biology, as well as evolutionary biology. No longer is the study of embryonic development merely “embryology.” In fact, development biology has produced - portant paradigms for both basic and clinical biomedical sciences alike. Although modern developmental biology has its roots in “experimental emb- ology” and the even more classical “chemical embryology,” the recent explosive and remarkable advances in developmental biology are critically linked to the advent of the “cellular and molecular biology revolution.” The impressive arsenal of expe- mental and analytical tools derived from cell and molecular biology, which promise to continue to expand, together with the exponentially developing sophistication in fu- tional imaging and information technologies, guarantee that the study of the devel- ing embryo will contribute one of the most captivating areas of biological research in the next millennium.