  Two classes of Gamma Ray Bursts have been identified so far, characterized by
T_90 durations shorter and longer than approximately 2 seconds. We show here
that the BATSE 3B data allow a good fit with three Gaussian distributions in
log T_90. The chi^2 statistic indicates a 40 % probability for two Gaussians,
whereas the three-Gaussian fit probability is 98 %. Using another statistical
method, it is argued that the probability that the third class is a random
fluctuation is less than 0.02 %.
