1. Biology Department; Wesleyan University; Middletown Connecticut 06459-0170
2. Gravida: National Centre for Growth & Development and Allan Wilson Centre for Molecular Ecology & Evolution, Department of Zoology; University of Otago; P.O. Box 56 Dunedin 9054 New Zealand
3. Department of Biology; Duke University; P.O. Box 90338 Durham North Carolina 27708