The Caenorhabditis elegans male: Postembryonic development of nongonadal structures

The nongonadal cells in the male nematode Caenorhabditis elegans have been followed through maturation by Nomarski microscopy. Many of the cells are incorporated into the copulatory apparatus, which includes the cloaca, copulatory spicules, sensilla, and musculature. This region has been reconstructed by serial section electron microscopy in order to identify the cell types that arise from known lineages. With the exception of certain bilaterally symmetrical pairs the cells have invariant fates. The development involves a variety of well-defined cell interactions, individual and collective cell movements, cell deaths mediated by designated killers, and the reorganisation of a muscle. The male structures overlie an almost unchanged hermaphrodite tail; their development is more complex than that of the hermaphrodite, and more liable to error.