252 Development of n Standardised Agar Medium 



where by their nmltiplication and further outward movement they 

 further extend the projection. In this manner, the colony is produced 

 into radiating branches (Fig. 2). In a branch, cells can be seen moving 

 toward the outward extremity so that the proximal region of the branch 



Fig. 2. B. dendroidcs. Young colony, diameter about 1 em. 



0&9 



.^^^:t'"- 



mW:^m 



>:^' 



Fig. 3. -B. dendroides. Young process from a surface colony (nutrient agar 12 hrs. 20° C). 



soon becomes partially depleted of cells, in many places only scattered 

 isolated cells remaining. Towards the outer end the cells are packed close 

 together and near the tip of the process they are piled up, two or more 

 layers of cells overlying one another (Fig. 3). This arrangement can be 



