This report is a summary of observations and collections made by P.O.B.S.P. personnel in the eastern Pacific Ocean from 11-24 March,1967. Participating personnel included Brian Harrington (biologist-in-charge), David Burckhalter, and James Lewis. Superior cooperation was received from the officers and crew of the U.S.N.S. SHEARWATER (T-AG 177). The grid track was followed as closely as circumstances would allow, but due to equipment failure and weather conditions a few deviations will be noted. First, on the night of 14-15 March a departure from the grid was made at point "D" in order to go to Port Hueneme for repair of the ship's steering. After two days in port, we returned to point "D" on the night of 17-18 March. The biologist in charge does not feel that this interrup- tion had any significant effect on grid observation data. Other deviations from the nominal track will be noted between points "G" and "H", and can be accounted for by the fact that the LORAN was inoperative, and due to cloudy weather there were no accurate fixes. Although not shown on map one, it is quite possible that the track between points "M" and "O" was also inaccurate for the same reason. Diurnal positions in this section of the grid should be considered accurate only to the nearest ten miles, and within five miles over the remainder of the grid cruise. All nocturnal positions are probably within ten miles. Eastern Grid Survey Number 4 The eastern grid survey was conducted from 1200 hours 12 March until 2345 hours 22 March, 1967 with an interruption of three days from 14-17 March. A total of 89.6 hours of diurnal observation were conducted over 826 linear miles. A summary may