Type species, _Staphylococcus aureus_ Rosenbach. Genus 6. _Micrococcus_ Cohn, 1872, emended Winslow and Rogers, 1905. Facultative parasites or saprophytes. Type species, _Micrococcus luteus_ (Schroeter, 1872) Cohn. Genus 7. _Sarcina_ Goodsir, 1842, emended Winslow and Rogers, 1905. Type species, _Sarcina ventriculi_ Goodsir. Genus 8. _Rhodococcus_ Zopf, 1891, emended Winslow and Rogers, 1905; cocci with red pigment. Type species, _Rhodococcus rhodochrous_ Zopf. FAMILY V--BACTERIACEÆ Cohn, 1872, emended by Committee of 1917; bacilli without spores not above included. Tribe I--CHROMOBACTEREÆ Committee of 1919; producing red or violet pigment, mainly water forms. Genus 1. _Erythrobacillus_ Fortineau, 1905. Type species, _Erythrobacillus prodigiosus_ (Ehrenberg, 1848) Fortineau. Genus 2. _Chromobacterium_ Bergonzini, 1881. Type species, _Chromobacterium violaceum_ Bergonzini. Tribe II--ERWINEÆ Committee 1919; plant pathogens. Genus 3. _Erwinia_ Committee 1917. Type species, _Erwinia amylovora_ (Burrill, 1883) Committee 1917. Tribe III--ZOPFEÆ Committee of 1919; Gram +, no pigment, non-carbohydrate-fermenting. Genus 4. _Zopfius_ Wenner and Rettger, 1919. Type species, _Zopfius zopfii_ (Kurth) Wenner and Rettger. Tribe IV--BACTEREÆ Committee of 1919; Gram -, carbohydrate fermenters. Genus 5. _Proteus_ Hauser, 1885; liquefy gelatin. Type species, _Proteus vulgaris_ Hauser. Genus 6. _Bacterium_ Ehrenberg, 1828, emended Jensen, 1909; liquefy gelatin rarely. Type species, _Bacterium coli_. Tribe VI--LACTOBACILLEÆ Committee of 1919; Gram +, high acid, thermophils. Genus 7. _Lactobacillus_ Beijerinck, 1901. Type species, _Lactobacillus caucasicus_ (Kern?) Beijerinck; Bulgarian bacillus. Tribe VI--PASTEURELLEÆ Committee of 1919; organisms of hemorrhagic septicemia. Genus 8. _Pasteurella_ Trevisan, 1888. Type species, _Pasteurella cholerae-gallinarum_ (Flügge, 1886); Trevisan. Tribe VII--HEMOPHILEÆ Committee of 1917; require hemoglobin for growth. Genus 9. _Hemophilus_ Committee of 1917. Type species, _Hemophilus influenzae_ (Pfeiffer, 1893) Committee of 1917. FAMILY VI--BACILLACEÆ Fischer, 1895. Spore forming rods. Genus 1. _Bacillus_ Cohn, 1872; aerobic, no change of form around the spore. Type species, _Bacillus subtilis_ Cohn. Genus 2. _Clostridium_ Prazmowski, 1880; anaërobic, frequently