THE FAMILIES AND GENERA OF THE BACTERIA 197 



C. ORDER CHLAMYDOBACTERIALES 3 



Cells normally united" in elongated filaments, often showing 

 false but never true branching. Typically water forms. Sul- 

 phur and bacterio-purpurin are absent. Iron often present and 

 usually a well-marked sheath. 



D. ORDER ACTINOMYCETALES Buchanan 1917a, p. 162 



Cells usually elongated, frequently filamentous and with a 

 decided tendency to the development of branches, in some gen- 

 era giving rise to the formation of a definite branched mycelium. 

 Cells frequently show swellings, clubbed or irregular shapes. 

 No pseudo-plasmodium. No deposits of free sulphur or iron. 

 No bacteriopurpurin. Endospores not produced, but conidia 

 developed in some genera. Usually Gram-positive. Non-mo- 

 tile. Some species are parasitic in animals or plants. Not water 

 forms. Complex proteins frequently required. As a rule 

 strongly aerobic, (except for some species of Actinomyces and the 

 genera Fusiformis and Leptotrichia) and oxidative. Growth on 

 culture media often slow; some genera show mold-like colonies. 



Family 1. Actinomycetaceae Buchanan 1918a, p. 403 



Filamentous forms often branched and sometimes forming my- 

 celia. Conidia sometimes present. Some species parasitic. 



Genus 1. Actinobacillus Brumpt, 1900, p. 849 



Filament formation, resembling streptobacilli. In lesions no 

 mycelium formed, but at peripheries finger shaped branched 

 cells are visible. Gram negative. Not acid fast. 



Type species, Act. Lignieresi Brumpt. 



Genus 2. Leptotrichia Trevisan 1879, p. 138 



Synonyms: Leptothrix Robin 1847, not Leptothrix Keutzing 1843; 

 not Leptothrix Zopf 1885; Rasmussenia Trevisan 1889. 



