36 MANUAL OF DETERMINATIVE BACTERIOLOGY 



The outline classification below is proposed by the Editorial Board of the 

 Manual for use in the present (6th) edition of the Manual. It is based on 

 those developed by Bergey et al. in earlier editions. These, in turn, were 

 based on the outline classifications developed bj^ Buchanan (Jour. Bact., 1, 

 1916, 591 ; 2, 1917, 155 ff.; 5, 1918, 27 ff.) and Winslow et al. (Jour. Bact., 5, 

 1920, 191). 



Phylum Schizo'phyta 



Class I. Schizophyceae 

 Class II. Schizomycetes 

 Order I. Eubacteriales 



Sub-Order I. Eubacteriineae (includes Corynebacteriaceae) 

 Sub-Order II. Caulobacteriineae 

 Sub-Order III. Rhodobacteriineae 

 Order II. Actinomyceiales (includes Mycobacterium, Actinomyces, 



and related genera) 

 Order III. Chlamydobacteriales 

 Family I. Leptotrichaceae 

 Family II. Crenothrichaceae 

 Family III. Beggiatoaceae 



Appendix Achromatiaceae 

 Order IV. Myxobacteriales 

 Order V. Spirochaetales 

 Supplement: Groups whose relationships are uncertain. 



Group I. Order Rickettsiales . Group II. Order Virales. Group III. 

 Family Borrelomycetaceae. 



In this, the arrangement of Schizomycetes as a class coordinate with 

 Schizophyceae, both belonging to a phylum Schizophyta of the plant king- 

 dom, is maintained as before. The number of orders is reduced from seven 

 as given in the fifth edition of the Manual to five, through recognition of 

 the fact that the rigid, unicellular, sometimes branching but never truly 

 mycelial nor filamentous organisms belonging to three of the previously 

 recognized orders are presumably more closely related to each other than 

 they are to the organisms in the four remaining orders. The family Coryne- 

 bacteriaceae has been transferred from the order Actinomyceiales to Eubac- 

 teriales. 



The colorless, filamentous, sulfur bacteria (Beggiatoaceae) have been 

 placed in the order Chlamydobacteriales with the other filamentous bacteria 

 that are clearly related to the blue-green algae. While this marks the 

 greatest deviation from the outline previously used, and separates these 

 colorless sulfur bacteria from the purple sulfur bacteria placed in Rhodo- 

 bacteriineae, it is in accordance with the arrangement accepted by Lehmann 

 and Neumann (Bakt. Diag., 4 Aufl., 2, 1907, 598), Pringsheim (Lotos, 71, 

 1923, 307) and others. Rhodobacteriineae is also limited to the purple and 

 green bacteria as suggested by Pringsheim Qoc. cit.) and accepted by Kluy- 

 ver and Van Niel (loc. cit.), by Stanier and Van Niel (loc. cit.) and others. 



