ACKNOWLEDGEMENTS The success of the survey was made possible by the cooperation of Cmdr. Donald J. Hackett, USN, Capt., and Lt. Cmdr. Walden, USN, Executive Officer, and members of the Walter A. crew of the USS Rehoboth, The kind help of Mr. James W. Winchester, Office of Naval Research, is greatly appreciated, as is also the help of the personnel of the U. 5S. Navy Hydrographic Office: Alfred W. Anderson William Cunningham William R. Deebel Blair W. Gibson Willis H. Hammond Gordon H. Knoop stanley G. Porter Joseph H. Rohrhirsch The authors are especially grateful for the assistance of Mr. Blair W. Gibson who spent many hours in the counting room, The authors also would like to acknowledge the invaluable assistance, advice and information obtained from the following personnel of the U. 5S. Navy Monitoring Team: Cmdr. F. W. Chambers, Jr., Head. Rad. Tech. Div. NMRI Lt. James W. Duckworth, Rad. Tech. Div. NMRI Ralph BE. Severence, HM1, Rad. Tech. Div. NMRI Lt. Cmdr. W. H. Chapman, Hq. AFSWP The support provided by Task Group 7.1 is hereby recognized.