The Molds 



47 



"ringworm," barber's itch, pityriasis, and tinea. Further 

 description of the organisms will be found in the section upon 

 Ringworm. 



3. Mucor. The mucors, or "black molds," belong to the 

 phy corny cetes. They form a thick, tangled mycelium, in 

 and above which the rounded black sporongia can be seen 

 with the naked eye. The mycelium becomes divided at the 

 time of reproduction. Multiplication takes place asexually 

 through conidia-spores which develop within sporangia, and 

 sexually by the conjugation of specialized terminal septate 



Fig. 1 1 . Mucor mucedo. Single-celled mycelium with three hyphae and 

 one developed sporangium (after Kny, from Tavel). 



branches of the mycelium, which conjugate with similar 

 cells, belonging to other colonies, to form zygospores. 



The sporangia form upon the ends of aerial hypha and con- 

 sist of a smooth spherical capsule within which the spores 

 develop, to become liberated only when the membrane rup- 

 tures. The colonies, each of which is unisexual, may be 

 described as + and . Colonies of the + type will not 

 conjugate; colonies of the type will not conjugate, but 

 when terminal filaments of + and come together, conjuga- 

 tion occurs and zygospore formation takes place. 



Mucors are not infrequent organisms of the atmosphere 

 and occasionally appear as contaminations upon solid culture- 

 media. About 130 species are known. Of these, Mucor 

 corymbifer, Mucor rhizopodiformis, Mucor ramosus, Mucor 



