66 MANUAL OF DETERMINATIVE BACTERIOLOGY 



2. Organisms forming elongated usually branching and mycelial cells. Multiply 

 by cell division, special spores, oidiospores and conidia. Sometimes acid-fast. 

 Non-motile. 



Order II. Actinomycetales, p. 895. 



3. Cells in filaments frequently enclosed in a tubular sheath with or without a de- 

 posit of ferric hydroxide. Sometimes attached. Motile flagellate and non- 

 motile conidia. Filaments sometimes motile with a gliding movement. Cells 

 sometimes contain free sulfur. 



Order III. Chlamydobacteriales , p. 981. 

 B. Cells flexuous, not rigid. 



1. Cells elongate. Motility, by creeping on substrate. 



Order IV. Myxobacteriales, p. 1005. 



2. Cells spiral. Motility, free swimming by flexion of cells. 



Order V. Spirochaetales, p. 1051. 

 Supplements: Groups whose relationships are uncertain. 



1. Obligate intracellular parasites or dependent directly on living cells. 



a. Not ultramicroscopic and only rarely filterable. More than 0.1 micron in 

 diameter. 



Group I. Order Rickettsiales , p. 1083. 

 aa. Usually ultramicroscopic and filterable. Except for certain pox viruses 

 of animals and a few plant viruses, less than 0.1 micron in diameter. 

 Group II. Order Virales, p. 1128. 



2. Grow in cell-free culture media with the development of polymorphic struc- 

 tures including rings, globules, filaments and minute reproductive bodies (less 

 than 0.3 micron in diameter). 



Group III. Family Borrelomycetaceae, p. 1291. 



ORDER I. EUBACTERIALES BUCHANAN. 



(Jour. Bact., g, 1917, 162.) 



Simple and undifferentiated rigid cells which are either spherical or rod-shaped. 

 The rods may be short or long, straight or curved or spiral. Some groups or species 

 are non-motile, others show locomotion by means of flagella. Elongated cells divide 

 by transverse fission and may remain attached to each other in chains. Spherical or- 

 ganisms divide either by parallel fission producing chains, or by fission alternating in 

 two or three planes producing thus either tetrads or cubes of 8 and multiples of 8 cells. 

 Many spherical cells form irregular masses in which the plane of division cannot be 

 ascertained. Endospores occur in some species. Some species are chromogenic, 

 but only in a few is the pigment photosynthetic (bacteriochlorophyll or other chloro- 

 phyll-like pigments). 



A group of rather large, spherical to short rod-shaped, colorless sulfur bacteria » 

 which some feel should be included in the order Eubacter tales, has been attached as 

 an Appendix to the order Chlamydobacteriales on account of the physiological similar- 

 ity between the former organisms and the Beggiatoaceae. These are in Family Achro- 

 matiaceae, p. 997. 



