The acrosomal bundle from Limulus sperm has been imaged to 7 Angstrom in a 400-kV electron cryomicroscope using the spot-scan technique. These images have been processed by Fourier averaging, corrected for the contrast transfer function, and merged to that resolution. The reconstructed density map of this projection shows features consistent with the 13-Angstrom projection map from a helical reconstruction and with the X-ray-derived model for F-actin, and regions of possible scruin-scruin contacts. (C) 1995 Academic Press, Inc.