Bacteria from twenty-one individual Tardigrada were isolated and identified
. The most common species found were members of the phytopathogenic genera
Xanthomonas and Pseudomonas. All of these isolates appear to have originate
d from the alimentary tracts of the tardigrades. The isolates probably are
not randomly associated with the tardigrades as repeated attempts to coloni
ze tardigrades with the Serratia marcescens bacterium failed. Tardigrades m
ay serve as vectors for plant pathogenic bacteria.