1. Department of Zoology, The Natural History Museum, London SW7 5BD, U.K.
2. Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Pontecorvo Building, 56 Dumbarton Road, Glasgow G11 6NU, U.K.
3. Frontier, 50–52 Rivington Street, London EC2A 3QP, U.K.
4. Department of Zoology and Marine Biology, P.O. Box 35064, University of Dar es Salaam, Dar es Salaam, Tanzania