The Morphology of Alcaligenes faecalis bacteriophages

The morphology of seven temperate phages from lysogenic strains of Alcaligenes faecalis and two virulent phages obtained from sewage and active on this species was examined by a negative-staining technique. The phages showed a variety of morphological forms and two of them have unusual combinations of features. One (All/A79) has a contractile tail sheath around a hollow core, but lacks the base plate, pins and tail fibres usually associated with this type of tail. The other (A5/A6) resembles the C1, F 1 group of coliphages but has an octahedral head and a collar. The five remaining temperate phages are similar to the C1, F 1 and Providence 9000/9402 group of phages. The sewage phages differ in many respects from one another and also from the temperate phages ex-amined. At least three of the nine phages have octahedral heads