1. Department of Anatomy and Physiology; Faculty of Veterinary Science; University of Pretoria; Private Bag X04 Onderstepoort 0110 South Africa
2. Ross University School of Veterinary Medicine; P.O. Box 334 Basseterre St. Kitts West Indies
3. Bristol Zoo Gardens; Clifton Bristol BS8 3HA UK
4. Johannesburg Zoo; Private Bag X13 Parkview Johannesburg 2122 South Africa