  We have analyzed the 241 bursts for which peak counts $\C$ exist in the
publicly available Burst and Transient Source Experiment (BATSE) catalog.
Introducing peak counts in 1024 ms as a measure of burst brightness $\B$ and
the ratio of peak counts in 64 and 1024 ms as a measure of short timescale
variability $\V$, we find a statistically significant correlation between the
brightness and the short timescale variability of \g-ray bursts. The bursts
which are smoother on short timescales are both faint and bright, while the
bursts which are variable on short timescales are faint only, suggesting the
existence of two distinct morphological classes of bursts.
