Pootjes, Christine F. (The Pennsylvania State University, University Park), R. B. Mayhew, and B. D. Korant. Isolation and characterization of Hydrogenomonas facilis bacteriophages under heterotrophic growth conditions. J. Bacteriol. 92:1787-1791. 1966.-We have isolated five strains of bacteriophage specific for Hydrogenomonas facilis. The host range of the phage is limited to H. facilis. Morphologically, the phage particles consist of a head 580 A in diameter and a short tail 200 A in length. The particles share a common surface antigen, and all contain deoxyribonucleic acid. The five strains differ from each other in growth characteristics, heat stability, and neutralizing antigens.