Until he retired in 1997, Donald I. Williamson was Reader in Marine Biology@the University of Liverpool in the United Kingdom. He specialized in marine plankton, particularly marine larvae. Most of his publications are on crustacean larvae. He is the author of Larvae and Evolution: Toward a New Zoology (Chapman and Hall, 1992) and The Origins of Larvae (Kluwer, 2003). Address: 14 Pairk Beg, Port Erin, Isle of Man IM9 6NH, UK. Internet: diwilliamson@manx.net