10 CONSIDERATIONS INFLUENCING CLASSIFICATION 



has previously been suggested for this entire group. This has caused Dr. C. B. 

 Phihp, who has acted as editor of the section covering rickettsias and related 

 species in the present (7th) edition of the Manual, to suggest the name Microta- 

 tobiotes for Class III. The latter is a more appropriate name for the entire group 

 of organisms included in the orders Rickettsiales and Virales than any that has 

 previously been suggested. Dr. Philip has discussed the new developments in the 

 classification of the order Rickettsiales in a recent paper (Canadian Jour. Micro- 

 biol., 2, 1956, 261). Therefore the present discussion is limited to an explanation 

 of the reasons for increasing the number of orders recognized in Class II, Schizo- 

 mycetes von Naegeli, from five to ten. 



The organisms placed in Class II, Schizomycetes von Naegeli, in the 6th edition 

 were arranged in five orders as follows: 



Division I. Schizophyta Cohn, 1875. (Fission plants.) 



Class I. Schizophyceae Cohn, 1879. (Fission algae. Blue-green algae.) 

 Class II. Schizomycetes von Naegeli, 1857. (Fission fungi, bacteria.) 

 Order I. Eubacteriales Buchanan, 1917 (The true bacteria.) 

 Order II. Aciinomycetales Buchanan, 1917. (The mycobacteria, actinomyces, 



streptomyces and related forms.) 

 Order III. Chlamydohacteriales Buchanan, 1917. (The alga-like, filamentous 



bacteria.) 

 Order IV. Myxobacteriales Jahn, 1911. (The slime bacteria.) 

 Order V. Spirochaetales Buchanan, 1918. (The spirochetes and related forms.) 



Supplements: Groups whose relationships were regarded as uncertain. 



Group I. Order Rickettsiales Buchanan and Buchanan, 1938, emend. Gieszczy- 



kiewicz, 1939. (Rickettsias and related organisms.) 

 Group II. Order Virales Breed, Murray and Hitchens, 1944. (Filterable viruses.) 

 Group III. Family Borrelomycetaceae Turner, 1935. (Pleuro-pneumonia-like organ- 

 isms.) 



This outline as given above is similar to the outline followed in earlier editions 

 of the Manual and is based upon the outline classification developed by Bu- 

 chanan (op. cit.) in 1916-18. It is expanded in the present edition of the Manual 

 as follows : 



Division I. Protophyta Sachs, 1874, emend. Krassilnikov, 1949.* (Primitive plants.) 

 Class I. Schizophyceae Cohn, 1879. (Blue-green algae.) 

 Class II. Schizomycetes von Naegeli, 1857. (Bacteria and related forms.) 



Order I. Pseudomonadales Orla- Jensen, 1921. 



Order II. Chlamydohacteriales Buchanan, 1917. 



Order III. Hyphomicrobiales Douglas, 1956. 



Order IV. Eubacteriales Buchanan, 1917. 



* Protophyta was previously used by Endlicher, S. (Genera Plantarum, Vindobonae, 

 1836, p. 1) in two different senses: (1) for Sectio I, Algae and Lichens of his Regio I Thal- 

 lophyta, (2) for Cohors II of his Sectio III, Acrobrya, to include horse tails, ferns, etc. This 

 use may be disregarded under Article 26 of the International Code of Botanical Nomen- 

 clature. This reads: "The rules of priority and typification do not apply to names of taxa 

 above the rank of orders.". 



