94 



THE ACTINOMYCETES, Vol. I 



The life cycle of Micromonospora was de- 

 scribed by Morris as follows: The spore 

 germinates by budding and the bud develops 

 into a long filamentous cell, which divides 

 into a number of individual cells by the for- 

 mation of transverse cell walls. The branches 

 are permanent, since no transverse w^all is 

 produced at the junction of the parent cell 

 and the branch. A haploid mycelium is thus 

 developed; the filamentous outgrowths from 

 the cell show a direct protoplasmic connec- 

 tion between cell and filament. Where two 



filaments make contact, an ovoid swelling 

 appears, forming a complete cell, eventually 

 enclosed in a cell w^all. These were believed 

 to be diploid. These cells give rise, on germi- 

 nation, to a "secondary mycelium," multi- 

 cellular in nature with permanent branching. 

 Single spores arise at the end of their stalks, 

 formed at first as finger-like protrusions of 

 the mycelium. 



The morphological features of the other 

 genera of actinomycetes are discussed in 

 Chapters 26 to 29 (Volume II). 



