Page:Bergey's manual of determinative bacteriology.djvu/35

 has shown that microorganisms that belong in this order sometimes exist in water rather than as pathogens affecting animals or plants or in soil. These water-inhabiting, saprophytic types of Actinomycetes have developed sporangia in which motile or non-motile spores may develop. In a way they are analogous to the so-called water molds. The structure of the vegetative cells and mycelia of these water-inhabiting Actinomycetes is like that of the aerobic Actinomycetes.

Order VII, Beggiatoales, has been organized by Dr. R. E. Buchanan, page 837, to include a group of bacteria, primarily ocurring in trichomes, that are motile but which lack flagella. In spite of this lack they have the power to glide, roll or oscillate as do certain species of blue-green algae. While none of these bacterial types develop photosynthetic pigments, they are frequently and apparently quite properly regarded as colorless, saprophytic forms of blue-green algae. Certain species oxidize sulfur compounds with the liberation of free sulfur granules. Some specialists prefer to transfer this group to Class I, Schizophyceae, as colorless species of blue-green algae rather than to include them with Class II, Schizomycetes. As bacteriologists have been primarily responsible for developing our knowledge of the species in this order, they are retained here in Class II, Schizomycetes.

Our knowledge of Order VIII, Myxobacterales, the so-called slime bacteria, was first developed by botanists rather than bacteriologists. These organisms occur in leaf mold and on the dung of animals. Recently species causing diseases of fish have been found. The cells of these species move with a flexuous motion in a slime which normally grows up into fruiting bodies large enough to be visible to the naked eye.

The organisms placed in Order IX, Spirochaetales, have always been set off by themselves though certain species are known that are so much like other species of bacteria placed in the genus Spirillum in Order I, Pseudomonadales, that they may be regarded as transitional forms. Sometimes, without sufficient justification, these spirally twisted organisms have been placed among the Protozoa.

The tenth order of Class II, Schizomycetes, is the newly organized Order X, Mycoplasmatales Freundt. Because a review of the nomenclature of the pleuropneumonia-like organisms (Buchanan, Cowan and Wikén, Internat. Bull. Bact. Nomen. and Taxon., 5, 1955, 13-20) has shown that the first generic name applied to these organisms that has a legitimate standing is Mycoplasma Nowak (Ann. Inst. Past., 43, 1929, 1330-1352), this name has been adopted for use in the classification of the pleuropneumonia-like organisms that has been prepared by Freundt (Internat. Bull. Bact. Nomen. and Taxon., 5, 1955, 67-78). This generic name has also been used by Edward (Internat. Bull. Bact. Nomen. and Taxon., 5, 1955, 85-93). While other order names, such as Borrelomycetales Turner (Jour. Path, and Bact., 41, 1935, 1-32), have been suggested, the generic name Borrelomyces Turner on which the order name is founded has never come into general use, and Borrelomyces is in fact an illegitimate homonym of Mycoplasma Nowak. Acceptance of the order name Mycoplasmatales is in accordance