1. Department of Veterinary Anatomy, School of Veterinary Medicine, Rakuno Gakuen University, 582, Midorimachi, Bunkyodai, Ebetsu, Hokkaido 069-8501, Japan
2. Menicon Co., Ltd., 5-1-10, Takamoridai, Kasugai, Aichi 478-0032, Japan
3. Faculty of Agriculture, Department of Veterinary Anatomy, Tottori University, 4-101, Koyama-Minami, Tottori 680-8550, Japan