Cover legend: Gustatory axon bundles innervating a mouse tongue. A scanning electron microscope image was superimposed on an image of the same tongue showing DiI-labeled fiber bundles. This overlay allowed visualization and quantification of innervated and uninnervated taste papillae. In this E16.5 wild-type tongue, most taste papillae are successfully innervated. For more information, see the article by Ma in this issue (pages 3354–3364).