22 A MANUAL OF BACTERIOLOGY 



in some species. Typically in water or infusions. (Sp. 

 rubrum. ) 



Family IV. COCCACEAE. Typically spherical cells. Division 

 in one, two or three planes. Endospores absent. Motility 

 rare. Pigment often produced. 



TRIBE A. NEISSEREAE. 



Strict parasites growing on serum media but not on ordinary 

 media (or only poorly on latter). Cells normally in pairs. Gram- 

 negative. 



Genus 1. NEISSERIA. Characters those of tribe. (Gonococcus 

 and Meningococcus. ) 



TRIBE B. STREPTOCOCCEAE. 



Parasites (except Leuconostoc). Planes of fission of cells usually 

 parallel so that chains are formed. Generally Gram-positive and 

 grow anaerobically. Produce acid in glucose and generally in 

 lactose. 



Genus 2. DIPLOCOCCUS. Parasites. Gram -positive. Often 

 encapsuled. Most ferment glucose, lactose, sucrose and 

 inulin. (Pneumococcus.) 

 Genus 3. LEUCONOSTOC. Saprophytes growing in sucrose. 



Cells in chains or pairs in zooglosal masses. 



Genus 4. STREPTOCOCCUS. Chiefly parasites. Cells normally 

 in short or long chains. Capsules rarely present, no zooglcea. 

 Generally Gram -positive. Growth delicate. Many sugars 

 fermented but rarely inulin. Generally non-liquefiers. 

 Genus 5. STAPHYLOCOCCUS. Parasites. Cells in groups. 

 Generally Gram -positive. Growth copious, white or orange. 

 Gelatin often liquefied. Ferment glucose, maltose, sucrose 

 and often lactose. 



TRIBE C. MICROCOCCEAE. 



Parasites or saprophytes, preferably aerobic. Copious growth. 

 Planes of fission often at right angles with packet formation. 

 Genus 6. MICROCOCCUS. Copious growth with yellow pig- 

 ment. 

 Genus 1. SARCINA. Cell-division in three planes with packet 



formation. 

 Genus 8. RHOPOCOCCUS. Copious growth with red pigment, 



