SUBFAMILIES AND GENERA OF COCCACE^E 85 



pigment-producers. Ammonia production, on the other 

 hand, appears in one in eight of the yellows, one in ten of 

 the orange forms, and not at all among the reds. 



CORRELATION BETWEEN CHROMOGENESIS AND OPTIMUM 

 TEMPERATURE FOR GROWTH. 



Number of cultures in each class. 



Optimum Temperature. 



20" 



20 or 37 c 

 37° 



Whi 



Yellow. 



67 



155 



3 2 



Orange 



13 

 126 



42 



Red. 



o 

 25 



The majority of forms grow equally^at either tempera- 

 ture. Among the white and orange forms, most of those 

 which exhibit any preference grow best at 37 degrees, 

 while among the yellows 20 degrees is more often the 

 optimum. These results accord with the habitats, respec- 

 tively parasitic and saprophytic, of the two classes. 



CORRELATION BETWEEN CHROMOGENESIS AND OPTIMUM 

 TEMPERATURE FOR COLOR PRODUCTION. 



Number of cultures in each class. 



It appears from the table that temperature differences 

 affect the production of orange pigment much more than 

 that of yellow; and that the body temperature interferes 

 with red chromogenesis most of all. 



