evolution. For the article “Naked corals: Skeleton loss in Scleractinia,” by Mónica Medina, Allen G. Collins, Tori L. Takaoka, Jennifer V. Kuehl, and Jeffrey L. Boore, which appeared in issue 24, June 13, 2006, of Proc. Natl. Acad. Sci. USA (103, 9096–9100; first published June 5, 2006; 10.1073/pnas.0602444103), the caption for the issue cover image appeared incorrectly, due to a PNAS error. The online version has been corrected. The corrected cover caption appears below.
Cover image: Oral view of the naked coral Discosoma sp. (Cnidaria: Anthozoa: Hexacorallia: Corallimorpharia). This coral species inhabits shallow tropical waters in the Indo-Pacific Sea. Corallimorpharians like this one appear to be scleractinian stony corals that, during the Cretaceous period, lost the ability to precipitate a calcium carbonate skeleton. See the article by Medina et al. on pages 9096–9100. Image courtesy of Mónica Medina and David Keys (Joint Genome Institute, Walnut Creek, CA).