THE CLASSIFICATION OF BACTERIA 37 



I \MILIES. 



I. Cells globose in a free state, not elongating in any 



direction before division into 1, 2, or 3 planes . 1. Coccacese. 

 II. Cells cylindrical, longer or shorter, and only divid- 

 ing in one plane, and elongating to about twice the 

 normal length before the division, 

 a. Cells straight, rod-shaped, without sheath, non- 

 motile, or motile by means of flagella . . . 2. Bacteriaceae. 

 6. Cells crooked, without sheath . . . .3. Spirillaceaj. 

 c. Cells enclosed in a sheath 4. Chlamydobacteriaceae. 



GENERA. 



1. Coccacece. 

 Ceils without organs of motion. 



a. Division in one plane 1. Streptococcus. 



b. Division in two planes 2. Micrococcus. 



c. Division in three planes . . . . .3. Sarcina. 

 Cells with organs of motion. 



a. Division in two planes 4. Planococcus. 



6. Division in three planes 5. Planosarcina. 



2. Bacteriacece. 



Cells without organs of motion . . . . .1. Bacterium. 

 Cells with organs of motion (flagella). 



a. Flagella distributed over the whole body . .2. Bacillus. 



b. Flagella polar 3. Psehdomonas. 



3. Spiriltacece. 

 Cells rigid, not snake-like or flexuous. 



a. Cells without organs of motion . . . .1. Spirosoma. 

 6. Cells with organs of motion (flagella). 



1. Cells with 1, very rarely 2 to 3 polar flagella . 2. Microspira. 



2. Cells with polar flagella-tufts ... 3. Spirillum. 

 Cells flexuous 4. Spirochseta. 



4. ChlamydobacteriacecB (higher bacteria). 



Cell contents without granules of sulphur. 



a. Cell threads unbranched. 

 I. Cell division always only in one plane . .1. Streptothrix. 



II. Cell division in three planes previous to the forma- 

 tion of gonidia. 



1. Cells surrounded by a very delicate, scarcely 



visible sheath (marine) ..... 2. Phragmidiothrix. 



2. Sheath clearly visible (in fresh water) . . .3. Crenothrix. 



6. Cell threads branched . . . . .4. Cladothrix. 

 Cell contents containing sulphur granules . . .5. Thiothrix. 



The above table makes changes in the designation of some of the most 

 common bacteria, as in the restoration of the old title bacterium and the 

 assigning to it of all non-motile, rod-shaped organisms, thus altering 

 the name of some of the most common pathogenic bacteria from bacillus 

 to bacterium. Other changes are seen in the spirilla. Any such scheme 



