BIOPHYSICS. For the article “An acoustic microscopy technique reveals hidden morphological defenses in Daphnia,” by Christian Laforsch, Wilfred Ngwa, Wolfgang Grill, and Ralph Tollrian, which appeared in issue 45, November 9, 2004, of Proc. Natl. Acad. Sci. USA (101, 15911–15914; first published November 1, 2004; 10.1073/pnas.0404860101), the authors note that the following statement should be added to the acknowledgements: “We thank the Deutsche Forschungsgemeinschaft for funding the project (Grant TO 171 4-1). The address where the induction experiments were performed is as follows: Ludwig Maximilians University Munich, Department of Biology II, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.”