1. Geologist at the U. S. Geological Survey, Denver, Colorado 80225
2. Associated with the University of Southern Florida, Tampa
3. Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela
4. Professor of environmental, population, and organismic biology at the University of Colorado, Boulder
5. Research associate at the Florida State Museum, University of Florida, Gainesville
6. Professors of biology at Indiana University, Bloomington
7. Escuela de Biologia, Universidad Central, Caracas, Venezuela