AGTINOMYCETEAE 



699 



unbranched sporogenous hyplia with little or no helical modification. This 

 seems to be associated with excessively rapid growth (e.g., Actinomyces alhus, 

 Fig. 114). 



The prevailing idea, that most of the mycelium is converted into spores, 

 is incorrect. Spomlation is strictly confined to terminal elements, never as a 

 rule passing beyond the first junction with another element (Fig. 115). The 

 proliferation of a branch nearest the end of the axial filament limits spore 

 production in this filament to the portion beyond the insertion of the first 



Fig. 114. — Actinomyces albus (A. griseus Krainsky ?). 1, 2, portions of aerial mycelium; 4, 

 germinating spore (X2,750). (After Drechsler 1919.) 



branch ; in the same manner, the proliferation of a secondary from a primary 

 lateral branch results in a sterilization of the portion of the hypha below the 

 insertion of the new branch. In Actinomyces Y, sporulation is even further 

 restricted by the apparent abortion of a number of potential spores at the 

 proximal end of the unbranched lateral branches. The hj-phal portion which 

 is involved first develops as usual, but when the characteristic septation asso- 

 ciated with the delimitation of spores in this species appears in the helix, it 

 is not extended to the base of the branch, although indications of regularly 

 spaced membranes may usually be distinguished. Later, the unsegmented 



