THE CHAEACTEEISTICS OF BACTEEIA 



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, 5) ; rhizoid, branched, 



Fig. 23. Types of bacterial colonies 

 A, conglomerate ; B, amoeboid ; C, rhizoid ; D, curled ; E, myceloid 



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

 strands like curly hair (Fig. 23, D') ; myceloid, fila- 

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



h. Size, approximately expressed in millimeters. 



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

 raised (Fig. 24, B') ; convex (Fig. 24, C) ; pulvinate, 

 surface a segment of a circle (Fig. 24, D) ; capi- 

 tate, surface a semisphere (Fig. 24, .ff) ; umbilicate, 

 depressed in the center (Fig. 24, F^ ; umbonate, 

 elevated at the center (Fig. 24, G). 



