  A systematic search for 22 GHz H2O megamaser emission is reported for 50
nearby (z < 0.15) FR I galaxies. No detection was obtained, implying that
ultraluminous H2O masers (L_H2O>10^3 L_sun) must be rare in early-type galaxies
with FR I radio morphology. Despite higher radio core luminosities the
detection rate for our sample is much lower than in similar surveys of
late-type Seyfert galaxies. This puzzling difference between Seyferts and
low-power radio galaxies could be explained in several ways: a) the maser
emission is saturated and therefore independent of the radio core luminosity,
b) the masers are unsaturated and the background continuum source is associated
with the counter jet which is beamed away and relativistically dimmed in
radio-galaxies, or c) the amount, kinematics, or the distribution of the
molecular gas in the nuclei of Seyferts and radio galaxies is different.
Further studies of maser properties may therefore hold a clue for morphological
differences between active nuclei of Seyfert and early-type radio galaxies.
