248 RELATIONSHIPS OF THE COCCACE^E 



cultures of M . agilis. Migula, on the other hand, shows in 

 Plate III of his System der Bakterien (1900) an excellent 

 photo-micrograph of a flagellated culture of M. agilis, 

 Hinterberger (1904), too, has published photo-micro- 

 graphs of flagella in a culture of M . agilis over ten months 

 old. Motility had been lost at this time, but the per- 

 sistence of flagella indicated a characteristic difference 

 from other forms. 



An organism identical with M. agilis, except for the 

 occurrence of the cells in packets, was described by Maurea 

 in 1892 under the name Sarcina mobilis. Migula (1897) 

 observed well-marked packets of eight to sixty- four cells in 

 cultures of M. agilis when grown on moist agar; and he 

 classes both forms in his genus Planosarcina. 



There seems no doubt from these observations, and 

 from the experience of many bacteriologists with stock 

 cultures of M. agilis, that motile flagellated rhodococci are 

 occasionally found. In the light of present knowledge, 

 however, the property seems to be a rare and exceptional 

 one. If this is the case, it seems best, from the viewpoint 

 adopted in this revision, not to retain a specific name for 

 these few peculiar strains. On the other hand, further 

 study may show that the property is of sufficiently common 

 occurrence to constitute a true type center of variation. 

 In that case, the relation of the motile forms to R. roseus 

 and R. fulvus can be determined by comparative studies, 

 and a new specific type may be intelligently recognized. 



