43 strains of L. monocytogenes, incubated at room temp, and 37[degree] C, all showed flagella. Gray''s flagella stain was applied to 24-hr. agar cultures, and motility was checked by plating suspensions on 0.65% semisolid tryptose agar at room temp. and at 37[degree] C. The authors found that L. monocytogenes is peritrichous with a max. of 4 flagella at room temp., and with a strong tendency to non-flagellation at 37[degree] C, with a small % of monotrichous and a few bi- and triflagellated forms. Where a single flagellum was found, the point of attachment was subterminal.