Correction

SPECIAL FEATURE, MICROBIOLOGY. For the article “Chains of magnetite crystals in the meteorite ALH84001: Evidence of biological origin” by E. Imre Friedmann, Jacek Wierzchos, Carmen Ascaso, and Michael Winklhofer, which appeared in number 5, February 27, 2001, of Proc. Natl. Acad. Sci. USA (98, 2176–2181), the authors note the following correction. On page 2178, left column, 2nd line from the bottom, insert after “fractured”: “along existing microscopic cracks to expose carbonate globules.”