BELATION TO ENVIRONMENT— CLASSIFICATION 37 



Bacteria (Schizomycetes) . — Fission fungi (chlorophyll free) with cell 

 division in one, two, or three directions of space. Many varieties 

 possess the power of forming endospores. Whenever motility 

 is present, it is carried on by means of flagella, or, more rarely, 

 by undulating membranes. 



Family I. Coccacb^. — Cells in free state perfectly spherical. 

 Division in one, two, or three directions of space, by which each 

 spherical cell divides into two, four, or eight segments, each 

 of which again develops into a perfect sphere. Endospore 

 formation rare. 



Genus I. Streptococcus. — Cells divide in one direction of space only, 

 for which reason, if they remain connected after fission, bead- 

 like chains may be formed. No organs of locomotion. 



Genus II. Micrococcus (Staphylococcus). — Cells divide in two 

 directions of space, whereby, if the cells remain connected after 

 fission, tetrad and grape-like clusters may be formed. No organs 

 of locomotion. 



Genus III. Sarcina. — Cells divide in three directions of space, 

 whereby, if they remain connected after fission, bale-like packets 

 are formed. No organs of locomotion. 



Genus IV. Planococcus. — Cells divide in two directions of space, 

 as in micrococcus, but possess flagella. 



Genus V. Planosarcina. — Cells divide in three directions of space 

 as in sarcina, but possess flagella. 



Family II. Bacteriace^. — Cells long or short, cyhndrical, straight, 

 never spiral. Division in one direction of space only, after pre- 

 liminary elongation of the, rods. 

 Genus I. Bacterium. — Cells without flagella, often with endospores.^ 

 Genus II. Bacillus. — Cells with peritrichal flagella, often with 



endospores. 

 Genus III. Pseudomonas. — Cells with polar flagella. Endospores 

 occur in a few species, but are rare. 



Family III. Spieillace^. — Cells spirally curved or representing a 

 part of a spiral curve. Division in one direction of space only, 

 after preceding elongation of cell. 



Genus I. Spirosoma. — Cells without organs of locomotion. Rigid. 



Genus II. Microspira. — Cells rigid, with one or, more rarely, two 

 or three polar undulated flagella. 



