ABSTRACT
I. INTRODUCTION Nematodes are generally small animals that superficially resemble miniature earthworms in overall shape. Although the morphology of Caenorhabditis elegans is very simple, the establishment or maintenance of this shape involves a large number of genes. Mutant C. elegans strains have been isolated in which worms are short and fat, abnormally long and thin, twisted into a left or right helix, or covered with irregular lumps. This chapter deals with experiments and observations that suggest how the basic shape of the nematode is first established during embryogenesis and why certain genes may be essential for normal morphogenesis.
