A SURVEY OF THE GALACTIC PLANE FOR 6.7-GHZ METHANOL MASERS .1. L=325-DEGREES-335-DEGREES B=-0-DEGREES.53-0-DEGREES.53

We report the results of the first complete survey of an area of the G alactic plane for maser emission from the 6.7-GHz 5(1)-->6(0) A(+) tra nsition of CH3OH, The survey covers a 10.6-deg(2) region of the Galact ic plane in the longitude range 325 degrees-335 degrees and latitude r ange -0 degrees.53-0 degrees.53. The survey is sensitive to masers wit h a peak flux density greater than similar to 2.6 Jy. The weakest mase r detected has a peak flux density of 2.3 Jy, and the strongest a peak flux density of 425 Jy. We detected a total of 50 distinct masers, 26 of which are new detections. We show that many 6.7-GHz CH3OH masers a re not associated with IRAS sources, and that some are associated with sources that have colours differing from those of a typical ultracomp act H II (UGH II) region. We estimate that the number of UCH II region s in the Galaxy is significantly more than suggested by IRAS-based est imates, possibly by more than a factor of 2.