The ostracodes described in this report are from material collected in Naval Petroleum Reserve No. 4, northern Alaska. The samples were obtained from well and seismograph shot holes drilled by Arctic Contractors and United States Geophysical Company and from field samples collected by the United States Geological Survey in the period from 1945 to 1948/ The earliest samples were processed for microfossils in Washington, but most of the material was prepared in the Fairbanks Laboratory of the Geological Survey.