1. Department of Anatomy; New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard; Old Westbury NY U.S.A.
2. Department of Anatomy; Howard University College of Medicine, 520 W St. NW, Numa Adams Building; Washington DC 20059 U.S.A.
3. Structure and Motion Lab; Royal Veterinary College, Hawkshead Lane, Hatfield; Hertfordshire AL9 7TA UK
4. Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology; Harvard University, 26 Oxford Street; Cambridge MA 02138 U.S.A.