MOLDS 



are no true transverse septa. Septa appear in many forms only when 

 fruiting begins, but in the opinion of some they merely separate the 

 living portions of the mycelium from those in which the cytoplasm is 

 dead or degenerating. The cytoplasm in the unseptate mycelium forms 

 one continuous mass; it contains a great many nuclei (Fig. 24, i and 



2). Each nucleus with the cyto- 

 plasm surrounding it, according 

 to Sachs, may be considered a 

 physiological unit acting in a 

 somewhat similar capacity as a 



' . '.* * V Ji^*^ 



,.- cell, or may be designated as an 



1 



. . 

 2 





\ 



FIG. 24. FIG. 25. 



FIG. 24. i, Part of the mycelium of Thamnidium elegans (Mucor}. 2, Ex- 

 tremity of a filament of Mucor circinelloides showing three swellings about to form 

 sporangia. 3, A spore of the same mold. 4, Yeast forms from the same mold. 

 (After Leger.) 



FIG. 25. i, Mycelial filament of Endomyces magnusii. 2, Extremity of a 

 filament of the same mold in the process of growth, with a dividing nucleus. 3 and 

 4, Filaments of Endomyces fibuliger. In 4, metachromatic corpuscles are seen 

 in the vacuoles. 5, Filament on the way to increase, from the same mold, the 

 nucleus dividing. 



energid. This view is not held by all observers, however. Con- 

 sidered thus, the mycelium represents the collection of a great many 

 indistinct cells which are not separated by walls. The Mucorinece, for 

 example, belong to this structural type. 



2. Other fungi, especially among the Ascomycetes, have a septate 

 mycelium, but one in which the transverse septa do not restrict cellular 



