1. Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Hyogo, Japan
2. Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Tochigi, Japan
3. Laboratory of Animal Molecular Morphology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Hyogo, Japan