MOLDS 



41 



There are, moreover, molds which show both these last two struc- 

 tural types, with transitional forms between the two. For instance, 

 in Endomyces magnusii, the mycelium, ordinarily consisting of areas, 



each containing many energids, 

 can in some parts progress to a 

 uninuclear cellular structure. 



The conidia or spores of many 

 molds may have either one or 

 many nuclei, according to the 



i^ 



Fig. 23. Fig. 24. 



Fig. 23. — I, Part of the mycelium of Thamnidium elegans (Mucor). 2, Ex- 

 tremity of a filament of Mucor circinello'ides showing three swellings about to form 

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

 CAfter Liger.) •>" 



Fig. 24. — 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 fihUiger. In 4, metachromatic corpusdes are seen 

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

 nucleus dividing. 



species. The spores of the Mucorinece for example always have many 

 nuclei (Fig. 23, 3); on the contrary, the ascospores of the Ascomycetes, 

 the conidia of PenicilUum and Aspergillus, contain generally but a 

 single nucleus. 



The yeast forms which result from the budding of the mycelium in 

 some molds, most frequently have a single nucleus (Figf. 23, 4); how- 

 ever, in some, Demaiium, are sometimes found yeast-forms containing 



