Hygrine (1) and four known trepane alkaloids (tropanone [2] 3α-tropanol [3], brugine [4], and tropan-3α-yl benzoate [5]) have been isolated from three Crossostylis species (Rhizophoraceae). The structures of two new alkaloids, tropan-3ot-yl cinnamate (6) and ferulate (7) were determined from the spectral data (ms, 1H- and I3C-nmr) and by partial synthesis. © 1983, American Chemical Society. All rights reserved.