1. Department of Zoology; National Museum of Nature and Science; 4-1-1 Amakubo Tsukuba Ibaraki 305-0005 Japan
2. Laboratory of Marine Biology; Faculty of Science; Kochi University; 2-5-1 Akebono-cho Kochi 780-8520 Japan
3. Oshima Experiment Station; Kinki University; 1790-4, Oshima Kushimoto Wakayama 649-3633 Japan