Contributions to Zoology, 71 (1/3) (2002)

The improbability of dorso-ventral axis inversion during animal evolution, as presumed by Geoffroy Saint Hilaire

J.A.M. van den Biggelaar , E. Edsinger-Gonzales , F.R. Schram

Faculty of Biology, Dept. of Experimental Zoology, University of Utrech Padualaan 8, 3584 CH Utrecht, Netherlands,JovandenBiggelaar@wanadoo.nl

Smithsonian Marine Station, Smithsonian Institution 701 Seaway Drive, Fort Pierce, FL 34949pelagosphera@hotmail.com

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam Mauritskade 57, 1092 AD, Amsterdam, Netherlandsschram@science.uva.nl

Keywords: amphistomy, axis inversion, deuterostomes, spiral cleavage, protostomes, gastrulation