TRICHOPHYTONEAE 



451 



times they seem to be formed by outgrowths of the pectinations of the pecti- 

 nate hyphae, or as a tangle of hyphae resulting from a number of short 

 branches near the tip of a hypha ; or, in other cases, of a dense tangle where 

 the structure cannot be distinguished. These organs, however, do not develop 

 further and their significance is still somewhat in doubt. 



In the genus Ectotricho'phyton, the close dense spirals are thought to be 

 closely related to similar spiral ornaments in Myxotrichum of the Gymnoas- 

 caceae. It should be remembered however that under certain environmental 

 conditions a similar coiling may occur in wholly unrelated groups. Although 

 in itself it would be of little significance, as an additional bit of evidence the 

 presence of these spiral hyphae supports the argument for the primitiveness 

 of Ectotrichophyton. 



Fig. 



80. — Arthrospores. 1, Trichophyton tonsurans; Z-T, Favotrichophyton violaceum; 8, 9, 

 Endodermophyton concentricmm. (After Ota & Langeron 1923.) 



From the description of Grigorakis, who seems to have worked wholly 

 with mass cultures, the origin of the secondary mycelium is not at all clear. 

 Apparently it is produced from aleurospores. Nothing is definitely stated as 

 to the number of nuclei per cell, but judging from Grigorakis' figures, the 

 mycelium would seem to be either uni- or binucleate, at least with fewer 

 nuclei than the primary mycelium. Fusion of aleurospores prior to germina- 

 tion has been noted in Ectotrichophyton but Grigorakis states there is no 

 nuclear fusion. Probably this represents a degeneration phenomenon such as 

 we frequently find in the yeasts where unsuccessful attempts at nuclear fusion 

 are made. Also the full significance of the hyphal fusions shown by Davidson, 

 Dowding & Buller (1932) is not yet clear, although they seem to be useful in 

 determining species. In the series tried, these authors were unable to find any 



