Claus Rasmussen1, John S Ascher2. 1. Department of Bioscience, Aarhus University, Ny Munkegade 114, bldg. 1540, DK-8000 Aarhus C, Denmark.; Email: alrunen@yahoo.com. 2. Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.; Email: dbsajs@nus.edu.sg.