152 MOULDS; FILAMENTOUS FUNGI; HYPHOMYCES. 



a large oval spore. The bulb is enclosed in a cap, the calu- 

 mella, which remains open when the spores ripen and become 

 scattered. 



Oidia or segmented moulds : The structure of these moulds 

 is very simple. They represent a transition-stage between 

 the moulds and the yeasts. At times they are typical moulds, 

 and then again they resemble the yeasts in structure. The 

 sporangium is very indistinct and often appears to be absent. 

 The spores are formed directly from the sporangium or from 

 the mycelium by a process of segmentation similar to that 



FIG. 61. 



Mucor stolonifer. (Mez.) 



seen in the penicillii. O'idium albicans or thrush fungus is 

 the type of this class. O'idium lactis is the cause of sour milk 

 and rancid butter. 



The actinomyces has heretofore been considered a fungus, 

 and because of its peculiar appearance was called the ray 

 fungus. It is still often referred to as the streptothrix mould 

 or fungus, but there can be no question that this organism 

 belongs to the higher bacteria, and not to the moulds. It is 

 really a transition-stage between the filamentous moulds and 

 the bacteria or fission fungi. Hektoen thoroughly investi- 



