Soil bacteria that hydrolyze starch were isolated by means of an elective culture medium with this polysaccharide as the sole source of carbon; their ability to decompose cellulose was then tested. Thirteen strains of cellulose decomposing bacteria were thus isolated from several Quebec soils. The bacteria have been assigned to three recognized genera under eight new specific names. Their elevation to species rank is based on differentiations comparable to those used in Bergey's Manual. The following new species have been proposed:Vibrio perimastix,Vibrio hyperion,Bacterium infirme,Bacillus vagans,Bacillus Kellermani,Bacillus soli,Bacillus torquens, andBacillus effluens.