  We characterize the bundle properties for three different strains of
\textit{B. subtilis} bacteria with various numbers of flagella. Our study
reveals that, surprisingly, the number of bundles is independent of the number
of flagella, and the formation of three bundles is always the most frequent
case. We assume that this relates to the fact that different mutants have the
same body length. There is no significant difference between the bundle width
and length for distinct strains, but the projected angle between the bundles
increases with the flagellar number. Furthermore, we find that the swimming
speed is anti-correlated with the projected angle between the bundles, and the
wobbling angle between the swimming direction and cell body increases with the
number of flagella. Our findings highlight the impact of geometrical properties
of bacteria such as body length and bundle configuration on their motility.
