A new classification method was proposed from the view point of relationship among microorganisms, which was based on the Adanson's thinking, Sheath's similarity value and the author's concept of center species.
According to this method, some reorientation for the classification of the family Micrococcaceae was made and the following results were obtained.
1) The classical genus Gaffkya should be integrated to the genus Staphylococcus.
2) The five, non-fermentative species, M. colpogenes, M. cryophilus, M. denitrificans, M. morrhuae and M. halodenitrificans should be excepted from the genus Micrococcus, because of their lower similarity values, while the other eleven, fermentative species constituted the genus Micrococcus.
3) The assignment of the species in the genus Peptococcus was found to be proper, and the Peptostreptococcus glycinophilus indicated a higher similarity value to the genus Peptococcus rather than to the genus Peptostreptococcus.
4) Amoung ten species which have been included in the classical genus Sarcina, the five species such as S. ventriculi, S. maxima, S. methanica, S. barkeri and S. litoralis should be omitted from this genus, because they have a lower similarity value to the center species, if all of these ten species were considered to be in the same genus.
It was proper that the residual five, aerobic and tetrad species constituted the genus Sarcina, because of their higher similarity values to the center species, S. flava.
5) The two, microaerophilic, fermentative and large tetrad species, S. ventriculi and S. maxima should be elevated to the genus Zymosarcina from the original subgenus.
6) The two, strictly anaerobic, methane-fermentative and relatively small tetrad species, S. methanica and S. barkeri should be included in the genus Metanococcus.
7) S. litoralis should be excepted from the genus Sercina and belonged to any other genus.
Various, originally heterogenous species have been included together in the classical genus Sarcina, probably owing to their morphological character of packet.
According to the author's method, each of these species was consequently placed in its proper genus respectively, and moreover, they had the specific correlated features to the genus.
8) The classical family Micrococcaceae should be reduced to a lower rank as the following two tribes, namely, the tribe Micrococceae including Staphylococcus, Micrococcus and Peptococcus, and the tribe Sarcineae including Sarcina, Zymosarcina and Methanococcus.