Data obtained from the study of living Nautilus have considerable meaning in the biologic interpretation of ammonoids and fossil nautiloids. From the point of view of the paleontologist studies of living Nautilus are greatly to be desired, and it is unfortunate that so little is known about this animal. The following notes are culled from several and mostly minor publications and pertain to the biology of living Nautilus. Unpublished observations by Dr. Curt Teichert formerly of the University of Melbourne and Dr. M. F. Glaessner formerly of Port Moresby, Papua, New Guinea, are also included. Miss Joyce Allan of the Australian Museum in Sydney kindly supplied literature references and checked the manuscript. Dr. William J. Clench of the Museum of Comparative Zoology furnished distribution data from the molluscan collection of the museum. The writer wishes to thank all those who have helped for their kind aid in gathering the information presented here. GEOGRAPHIC DISTRIBUTION Living Nautilus is restricted to the southwest Pacific. Its geographic range is from South Australia [this is a significant extension of the previously known range; see Riddle, 1920] in the southwest to the Fiji Islands in the east, [but it does not occur farther east in the Samoa Islands (Bennett, 1859)] to the south coast of the Philippine Island Luzon (Talavera and Faustino, 1931) in the north and to Macassar Strait in the northwest, beyond which it does not seem to live (Willey 1902, p. 745). The center of distribution is the group of islands from...