THE CHARACTERISTICS OF BACTERIA 45 



5. Plate cultures. 

 a. Surface colonies. 



I. Naked-eye appearance. 



a. Form : punctiform, too small to be defined by the 

 naked eye; circular; oval; spindle-shaped; conglom- 

 erate, an aggregate of similar colonies (Fig. 23, A); 

 amoeboid, very irregular (Fig. 23, B) ; rhizoid, branched, 



FIG. 23. Types of bacterial colonies 

 A, conglomerate; 7?, amoeboid ; C, rhizoid ; J), curled ; H, myceloid 



rootlike structure (Fig. 23, 6') ; curled, filaments in 

 strands like curly hair (Fig. 23, 7>) ; myceloid, fila- 

 mentous with the character of a mold (Fig. 23, E). 



b. Size, approximately expressed in millimeters. ' 



c. Surface elevation: flat (Fig. 24, A) ; spreading; 

 raised (Fig. 24, J5) ; convex (Fig. 24, C) ; pulvinatc, 

 surface a segment of a circle (Fig. 24, 7>) ; ra/ri- 

 tate, surface a semisphere (Fig. 24, E) ; utnbiHct<\ 

 depressed in the center (Fig. 24, F) ; 

 elevated at the center (Fig. 24, ). 



