(1) Selection of 14 phages from the 47 phages available was assisted by determination of the Sneath-Jaccard similarity coefficients and subsequent unweighted pair-group arithmetic averaging cluster analysis.
(2) As an alternative we consider the advantages of the polythetic classification strategy as suggested by Sokal and Sneath (1963) in their description of a "numerical taxonomic" approach.
(3) OVCLUST is an implementation of the program described by Sneath (1979) which calculates overlap statistics between major clusters.
(4) These larger groups appeared to form reasonably distinct clusters when tested by Sneath's overlap statistics.
(5) The results have been subjected to computer analysis using the coefficient of Jaccard-Sneath and the strains clustered by the method of aggregation according to the variance.
(6) The acidification patterns were not adequate to differentiate Bifidobacterium species, as determined previously by Mitsuoka (Bifidobacteria Microflora 3:11-28, 1984) and Scardovi (p. 1418-1434, in P. H. A. Sneath, N. S. Mair, M. E. Sharpe, and J. G. Holt, ed., Bergey's Manual of Systematic Bacteriology, vol.